diff --git a/.github/workflows/full_ci.yml b/.github/workflows/full_ci.yml
index b36f4f9d2ba57..080ce790791f9 100644
--- a/.github/workflows/full_ci.yml
+++ b/.github/workflows/full_ci.yml
@@ -154,13 +154,7 @@ jobs:
           stable,
           beta,
           nightly,
-          # FIXME: Disabled due to:
-          # error: failed to parse registry's information for: serde
-          #1.13.0,
-          1.19.0,
-          1.24.0,
-          1.25.0,
-          1.30.0,
+          1.31.0,
         ]
     steps:
       - uses: actions/checkout@v4
@@ -205,10 +199,6 @@ jobs:
       fail-fast: true
       matrix:
         toolchain: [
-          1.19.0,
-          1.24.0,
-          1.25.0,
-          1.30.0,
           stable,
         ]
     steps:
diff --git a/README.md b/README.md
index 395b94ce0c8f3..6736b12a3f687 100644
--- a/README.md
+++ b/README.md
@@ -51,18 +51,13 @@ libc = "0.2"
 
 ## Rust version support
 
-The minimum supported Rust toolchain version is currently **Rust 1.13.0**.
+The minimum supported Rust toolchain version is currently **Rust 1.31.0**.
 (libc does not currently have any policy regarding changes to the minimum
 supported Rust version; such policy is a work in progress.) APIs requiring
 newer Rust features are only available on newer Rust toolchains:
 
 | Feature              | Version |
 |----------------------|---------|
-| `union`              |  1.19.0 |
-| `const mem::size_of` |  1.24.0 |
-| `repr(align)`        |  1.25.0 |
-| `extra_traits`       |  1.25.0 |
-| `core::ffi::c_void`  |  1.30.0 |
 | `repr(packed(N))`    |  1.33.0 |
 | `cfg(target_vendor)` |  1.33.0 |
 | `const-extern-fn`    |  1.62.0 |
diff --git a/build-tmp.rs b/build-tmp.rs
index 101f45ac262e9..ae588de1a68e4 100644
--- a/build-tmp.rs
+++ b/build-tmp.rs
@@ -15,22 +15,16 @@ const ALLOWED_CFGS: &'static [&'static str] = &[
     "freebsd13",
     "freebsd14",
     "freebsd15",
-    "libc_align",
     "libc_cfg_target_vendor",
     "libc_const_extern_fn",
     "libc_const_extern_fn_unstable",
-    "libc_const_size_of",
-    "libc_core_cvoid",
     "libc_deny_warnings",
-    "libc_int128",
     "libc_long_array",
     "libc_non_exhaustive",
     "libc_packedN",
-    "libc_priv_mod_use",
     "libc_ptr_addr_of",
     "libc_thread_local",
     "libc_underscore_const_names",
-    "libc_union",
     "libc_ctest",
 ];
 
@@ -95,38 +89,6 @@ fn main() {
         set_cfg("libc_deny_warnings");
     }
 
-    // Rust >= 1.15 supports private module use:
-    if rustc_minor_ver >= 15 || rustc_dep_of_std {
-        set_cfg("libc_priv_mod_use");
-    }
-
-    // Rust >= 1.19 supports unions:
-    if rustc_minor_ver >= 19 || rustc_dep_of_std {
-        set_cfg("libc_union");
-    }
-
-    // Rust >= 1.24 supports const mem::size_of:
-    if rustc_minor_ver >= 24 || rustc_dep_of_std {
-        set_cfg("libc_const_size_of");
-    }
-
-    // Rust >= 1.25 supports repr(align):
-    if rustc_minor_ver >= 25 || rustc_dep_of_std || align_cargo_feature {
-        set_cfg("libc_align");
-    }
-
-    // Rust >= 1.26 supports i128 and u128:
-    if rustc_minor_ver >= 26 || rustc_dep_of_std {
-        set_cfg("libc_int128");
-    }
-
-    // Rust >= 1.30 supports `core::ffi::c_void`, so libc can just re-export it.
-    // Otherwise, it defines an incompatible type to retaining
-    // backwards-compatibility.
-    if rustc_minor_ver >= 30 || rustc_dep_of_std {
-        set_cfg("libc_core_cvoid");
-    }
-
     // Rust >= 1.33 supports repr(packed(N)) and cfg(target_vendor).
     if rustc_minor_ver >= 33 || rustc_dep_of_std {
         set_cfg("libc_packedN");
diff --git a/build.rs b/build.rs
index ce4541e62955c..9c42cf6fabf00 100644
--- a/build.rs
+++ b/build.rs
@@ -14,22 +14,16 @@ const ALLOWED_CFGS: &'static [&'static str] = &[
     "freebsd13",
     "freebsd14",
     "freebsd15",
-    "libc_align",
     "libc_cfg_target_vendor",
     "libc_const_extern_fn",
     "libc_const_extern_fn_unstable",
-    "libc_const_size_of",
-    "libc_core_cvoid",
     "libc_deny_warnings",
-    "libc_int128",
     "libc_long_array",
     "libc_non_exhaustive",
     "libc_packedN",
-    "libc_priv_mod_use",
     "libc_ptr_addr_of",
     "libc_thread_local",
     "libc_underscore_const_names",
-    "libc_union",
     "libc_ctest",
 ];
 
@@ -94,38 +88,6 @@ fn main() {
         set_cfg("libc_deny_warnings");
     }
 
-    // Rust >= 1.15 supports private module use:
-    if rustc_minor_ver >= 15 || rustc_dep_of_std {
-        set_cfg("libc_priv_mod_use");
-    }
-
-    // Rust >= 1.19 supports unions:
-    if rustc_minor_ver >= 19 || rustc_dep_of_std {
-        set_cfg("libc_union");
-    }
-
-    // Rust >= 1.24 supports const mem::size_of:
-    if rustc_minor_ver >= 24 || rustc_dep_of_std {
-        set_cfg("libc_const_size_of");
-    }
-
-    // Rust >= 1.25 supports repr(align):
-    if rustc_minor_ver >= 25 || rustc_dep_of_std || align_cargo_feature {
-        set_cfg("libc_align");
-    }
-
-    // Rust >= 1.26 supports i128 and u128:
-    if rustc_minor_ver >= 26 || rustc_dep_of_std {
-        set_cfg("libc_int128");
-    }
-
-    // Rust >= 1.30 supports `core::ffi::c_void`, so libc can just re-export it.
-    // Otherwise, it defines an incompatible type to retaining
-    // backwards-compatibility.
-    if rustc_minor_ver >= 30 || rustc_dep_of_std {
-        set_cfg("libc_core_cvoid");
-    }
-
     // Rust >= 1.33 supports repr(packed(N)) and cfg(target_vendor).
     if rustc_minor_ver >= 33 || rustc_dep_of_std {
         set_cfg("libc_packedN");
diff --git a/ci/build.sh b/ci/build.sh
index d90872f4e8c84..561dd64ff97a4 100644
--- a/ci/build.sh
+++ b/ci/build.sh
@@ -169,15 +169,9 @@ case "${OS}" in
     linux*)
         TARGETS="${RUST_LINUX_TARGETS}"
 
-        if [ "${RUST}" != "1.13.0" ]; then
-            TARGETS="${TARGETS} ${RUST_GT_1_13_LINUX_TARGETS}"
-            if [ "${RUST}" != "1.19.0" ]; then
-                TARGETS="${TARGETS} ${RUST_GT_1_19_LINUX_TARGETS}"
-                if [ "${RUST}" != "1.24.0" ]; then
-                    TARGETS="${TARGETS} ${RUST_GT_1_24_LINUX_TARGETS}"
-                fi
-            fi
-        fi
+        TARGETS="${TARGETS} ${RUST_GT_1_13_LINUX_TARGETS}"
+        TARGETS="${TARGETS} ${RUST_GT_1_19_LINUX_TARGETS}"
+        TARGETS="${TARGETS} ${RUST_GT_1_24_LINUX_TARGETS}"
 
         if [ "${RUST}" = "nightly" ]; then
             TARGETS="${TARGETS} ${RUST_NIGHTLY_LINUX_TARGETS}"
diff --git a/libc-test/build.rs b/libc-test/build.rs
index 75dcd14fc83be..00caec688d3a5 100644
--- a/libc-test/build.rs
+++ b/libc-test/build.rs
@@ -69,11 +69,6 @@ fn do_ctest() {
 fn ctest_cfg() -> ctest::TestGenerator {
     let mut cfg = ctest::TestGenerator::new();
     let libc_cfgs = [
-        "libc_priv_mod_use",
-        "libc_union",
-        "libc_const_size_of",
-        "libc_align",
-        "libc_core_cvoid",
         "libc_packedN",
         "libc_thread_local",
     ];
diff --git a/src/fixed_width_ints.rs b/src/fixed_width_ints.rs
index 999de8f54f194..980ff61ecdaf3 100644
--- a/src/fixed_width_ints.rs
+++ b/src/fixed_width_ints.rs
@@ -20,7 +20,7 @@ pub type uint32_t = u32;
 pub type uint64_t = u64;
 
 cfg_if! {
-    if #[cfg(all(libc_int128, target_arch = "aarch64", not(target_os = "windows")))] {
+    if #[cfg(all(target_arch = "aarch64", not(target_os = "windows")))] {
         // This introduces partial support for FFI with __int128 and
         // equivalent types on platforms where Rust's definition is validated
         // to match the standard C ABI of that platform.
diff --git a/src/fuchsia/mod.rs b/src/fuchsia/mod.rs
index 9414d1674f26e..d0760fc34d318 100644
--- a/src/fuchsia/mod.rs
+++ b/src/fuchsia/mod.rs
@@ -4362,33 +4362,8 @@ cfg_if! {
     }
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        #[macro_use]
-        mod align;
-    } else {
-        #[macro_use]
-        mod no_align;
-    }
-}
+#[macro_use]
+mod align;
 expand_align!();
 
-cfg_if! {
-    if #[cfg(libc_core_cvoid)] {
-        pub use ::ffi::c_void;
-    } else {
-        // Use repr(u8) as LLVM expects `void*` to be the same as `i8*` to help
-        // enable more optimization opportunities around it recognizing things
-        // like malloc/free.
-        #[repr(u8)]
-        #[allow(missing_copy_implementations)]
-        #[allow(missing_debug_implementations)]
-        pub enum c_void {
-            // Two dummy variants so the #[repr] attribute can be used.
-            #[doc(hidden)]
-            __variant1,
-            #[doc(hidden)]
-            __variant2,
-        }
-    }
-}
+pub use ::ffi::c_void;
\ No newline at end of file
diff --git a/src/fuchsia/no_align.rs b/src/fuchsia/no_align.rs
deleted file mode 100644
index 7ca90e0e48a39..0000000000000
--- a/src/fuchsia/no_align.rs
+++ /dev/null
@@ -1,129 +0,0 @@
-macro_rules! expand_align {
-    () => {
-        s! {
-            pub struct pthread_mutexattr_t {
-                #[cfg(target_arch = "x86_64")]
-                __align: [::c_int; 0],
-                #[cfg(not(target_arch = "x86_64"))]
-                __align: [::c_long; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_MUTEXATTR_T],
-            }
-
-            pub struct pthread_rwlockattr_t {
-                __align: [::c_long; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_RWLOCKATTR_T],
-            }
-
-            pub struct pthread_condattr_t {
-                __align: [::c_int; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_CONDATTR_T],
-            }
-        }
-
-        s_no_extra_traits! {
-            pub struct pthread_mutex_t {
-                #[cfg(any(target_arch = "arm",
-                          all(target_arch = "x86_64",
-                              target_pointer_width = "32")))]
-                __align: [::c_long; 0],
-                #[cfg(not(any(target_arch = "arm",
-                              all(target_arch = "x86_64",
-                                  target_pointer_width = "32"))))]
-                __align: [::c_longlong; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_MUTEX_T],
-            }
-
-            pub struct pthread_rwlock_t {
-                __align: [::c_long; 0],
-                __align: [::c_longlong; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_RWLOCK_T],
-            }
-
-            pub struct pthread_cond_t {
-                __align: [*const ::c_void; 0],
-                #[cfg(not(target_env = "musl"))]
-                __align: [::c_longlong; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_COND_T],
-            }
-        }
-
-        cfg_if! {
-            if #[cfg(feature = "extra_traits")] {
-                impl PartialEq for pthread_cond_t {
-                    fn eq(&self, other: &pthread_cond_t) -> bool {
-                        // Ignore __align field
-                        self.size
-                            .iter()
-                            .zip(other.size.iter())
-                            .all(|(a,b)| a == b)
-                    }
-                }
-                impl Eq for pthread_cond_t {}
-                impl ::fmt::Debug for pthread_cond_t {
-                    fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
-                        f.debug_struct("pthread_cond_t")
-                            // Ignore __align field
-                            // FIXME: .field("size", &self.size)
-                            .finish()
-                    }
-                }
-                impl ::hash::Hash for pthread_cond_t {
-                    fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
-                        // Ignore __align field
-                        self.size.hash(state);
-                    }
-                }
-
-                impl PartialEq for pthread_mutex_t {
-                    fn eq(&self, other: &pthread_mutex_t) -> bool {
-                        // Ignore __align field
-                        self.size
-                            .iter()
-                            .zip(other.size.iter())
-                            .all(|(a,b)| a == b)
-                    }
-                }
-                impl Eq for pthread_mutex_t {}
-                impl ::fmt::Debug for pthread_mutex_t {
-                    fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
-                        f.debug_struct("pthread_mutex_t")
-                            // Ignore __align field
-                            // FIXME: .field("size", &self.size)
-                            .finish()
-                    }
-                }
-                impl ::hash::Hash for pthread_mutex_t {
-                    fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
-                        // Ignore __align field
-                        self.size.hash(state);
-                    }
-                }
-
-                impl PartialEq for pthread_rwlock_t {
-                    fn eq(&self, other: &pthread_rwlock_t) -> bool {
-                        // Ignore __align field
-                        self.size
-                            .iter()
-                            .zip(other.size.iter())
-                            .all(|(a,b)| a == b)
-                    }
-                }
-                impl Eq for pthread_rwlock_t {}
-                impl ::fmt::Debug for pthread_rwlock_t {
-                    fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
-                        f.debug_struct("pthread_rwlock_t")
-                            // Ignore __align field
-                            // FIXME: .field("size", &self.size)
-                            .finish()
-                    }
-                }
-                impl ::hash::Hash for pthread_rwlock_t {
-                    fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
-                        // Ignore __align field
-                        self.size.hash(state);
-                    }
-                }
-            }
-        }
-    };
-}
diff --git a/src/lib.rs b/src/lib.rs
index 764d8e4cd096a..b1a57a35de9cc 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -43,52 +43,25 @@ cfg_if! {
     }
 }
 
-cfg_if! {
-    if #[cfg(libc_priv_mod_use)] {
-        #[cfg(libc_core_cvoid)]
-        #[allow(unused_imports)]
-        use core::ffi;
-        #[allow(unused_imports)]
-        use core::fmt;
-        #[allow(unused_imports)]
-        use core::hash;
-        #[allow(unused_imports)]
-        use core::num;
-        #[allow(unused_imports)]
-        use core::mem;
-        #[doc(hidden)]
-        #[allow(unused_imports)]
-        use core::clone::Clone;
-        #[doc(hidden)]
-        #[allow(unused_imports)]
-        use core::marker::{Copy, Send, Sync};
-        #[doc(hidden)]
-        #[allow(unused_imports)]
-        use core::option::Option;
-    } else {
-        #[doc(hidden)]
-        #[allow(unused_imports)]
-        pub use core::fmt;
-        #[doc(hidden)]
-        #[allow(unused_imports)]
-        pub use core::hash;
-        #[doc(hidden)]
-        #[allow(unused_imports)]
-        pub use core::num;
-        #[doc(hidden)]
-        #[allow(unused_imports)]
-        pub use core::mem;
-        #[doc(hidden)]
-        #[allow(unused_imports)]
-        pub use core::clone::Clone;
-        #[doc(hidden)]
-        #[allow(unused_imports)]
-        pub use core::marker::{Copy, Send, Sync};
-        #[doc(hidden)]
-        #[allow(unused_imports)]
-        pub use core::option::Option;
-    }
-}
+#[allow(unused_imports)]
+use core::ffi;
+#[allow(unused_imports)]
+use core::fmt;
+#[allow(unused_imports)]
+use core::hash;
+#[allow(unused_imports)]
+use core::num;
+#[allow(unused_imports)]
+use core::mem;
+#[doc(hidden)]
+#[allow(unused_imports)]
+use core::clone::Clone;
+#[doc(hidden)]
+#[allow(unused_imports)]
+use core::marker::{Copy, Send, Sync};
+#[doc(hidden)]
+#[allow(unused_imports)]
+use core::option::Option;
 
 cfg_if! {
     if #[cfg(windows)] {
diff --git a/src/macros.rs b/src/macros.rs
index beb80024dbfa3..57956ccb81241 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -90,19 +90,15 @@ macro_rules! s_no_extra_traits {
         s_no_extra_traits!(it: $(#[$attr])* pub $t $i { $($field)* });
     )*);
     (it: $(#[$attr:meta])* pub union $i:ident { $($field:tt)* }) => (
-        cfg_if! {
-            if #[cfg(libc_union)] {
-                __item! {
-                    #[repr(C)]
-                    $(#[$attr])*
-                    pub union $i { $($field)* }
-                }
+        __item! {
+            #[repr(C)]
+            $(#[$attr])*
+            pub union $i { $($field)* }
+        }
 
-                impl ::Copy for $i {}
-                impl ::Clone for $i {
-                    fn clone(&self) -> $i { *self }
-                }
-            }
+        impl ::Copy for $i {}
+        impl ::Clone for $i {
+            fn clone(&self) -> $i { *self }
         }
     );
     (it: $(#[$attr:meta])* pub struct $i:ident { $($field:tt)* }) => (
@@ -286,16 +282,9 @@ macro_rules! align_const {
     ($($(#[$attr:meta])*
        pub const $name:ident : $t1:ty
        = $t2:ident { $($field:tt)* };)*) => ($(
-        #[cfg(libc_align)]
-        $(#[$attr])*
-        pub const $name : $t1 = $t2 {
-            $($field)*
-        };
-        #[cfg(not(libc_align))]
         $(#[$attr])*
         pub const $name : $t1 = $t2 {
             $($field)*
-            __align: [],
         };
     )*)
 }
diff --git a/src/psp.rs b/src/psp.rs
index a4ca029b6e0c1..b196e30e1e617 100644
--- a/src/psp.rs
+++ b/src/psp.rs
@@ -27,25 +27,7 @@ pub type c_char = u8;
 pub type c_long = i64;
 pub type c_ulong = u64;
 
-cfg_if! {
-    if #[cfg(libc_core_cvoid)] {
-        pub use ::ffi::c_void;
-    } else {
-        // Use repr(u8) as LLVM expects `void*` to be the same as `i8*` to help
-        // enable more optimization opportunities around it recognizing things
-        // like malloc/free.
-        #[repr(u8)]
-        #[allow(missing_copy_implementations)]
-        #[allow(missing_debug_implementations)]
-        pub enum c_void {
-            // Two dummy variants so the #[repr] attribute can be used.
-            #[doc(hidden)]
-            __variant1,
-            #[doc(hidden)]
-            __variant2,
-        }
-    }
-}
+pub use ::ffi::c_void;
 
 pub type SceKernelVTimerHandler = unsafe extern "C" fn(
     uid: SceUid,
diff --git a/src/sgx.rs b/src/sgx.rs
index 7da6269399d9e..0c62ee2832a89 100644
--- a/src/sgx.rs
+++ b/src/sgx.rs
@@ -26,22 +26,4 @@ pub type c_ulong = u64;
 pub const INT_MIN: c_int = -2147483648;
 pub const INT_MAX: c_int = 2147483647;
 
-cfg_if! {
-    if #[cfg(libc_core_cvoid)] {
-        pub use ::ffi::c_void;
-    } else {
-        // Use repr(u8) as LLVM expects `void*` to be the same as `i8*` to help
-        // enable more optimization opportunities around it recognizing things
-        // like malloc/free.
-        #[repr(u8)]
-        #[allow(missing_copy_implementations)]
-        #[allow(missing_debug_implementations)]
-        pub enum c_void {
-            // Two dummy variants so the #[repr] attribute can be used.
-            #[doc(hidden)]
-            __variant1,
-            #[doc(hidden)]
-            __variant2,
-        }
-    }
-}
+pub use ::ffi::c_void;
diff --git a/src/solid/mod.rs b/src/solid/mod.rs
index f0f2ae89bde90..5db97f948cd02 100644
--- a/src/solid/mod.rs
+++ b/src/solid/mod.rs
@@ -871,25 +871,7 @@ extern "C" {
     pub fn lseek(arg1: c_int, arg2: __off_t, arg3: c_int) -> __off_t;
 }
 
-cfg_if! {
-    if #[cfg(libc_core_cvoid)] {
-        pub use ::ffi::c_void;
-    } else {
-        // Use repr(u8) as LLVM expects `void*` to be the same as `i8*` to help
-        // enable more optimization opportunities around it recognizing things
-        // like malloc/free.
-        #[repr(u8)]
-        #[allow(missing_copy_implementations)]
-        #[allow(missing_debug_implementations)]
-        pub enum c_void {
-            // Two dummy variants so the #[repr] attribute can be used.
-            #[doc(hidden)]
-            __variant1,
-            #[doc(hidden)]
-            __variant2,
-        }
-    }
-}
+pub use ::ffi::c_void;
 
 cfg_if! {
     if #[cfg(target_arch = "aarch64")] {
diff --git a/src/switch.rs b/src/switch.rs
index 030ab20d7bd8e..f2b485964b9a4 100644
--- a/src/switch.rs
+++ b/src/switch.rs
@@ -28,22 +28,4 @@ pub type wchar_t = u32;
 pub const INT_MIN: c_int = -2147483648;
 pub const INT_MAX: c_int = 2147483647;
 
-cfg_if! {
-    if #[cfg(libc_core_cvoid)] {
-        pub use ::ffi::c_void;
-    } else {
-        // Use repr(u8) as LLVM expects `void*` to be the same as `i8*` to help
-        // enable more optimization opportunities around it recognizing things
-        // like malloc/free.
-        #[repr(u8)]
-        #[allow(missing_copy_implementations)]
-        #[allow(missing_debug_implementations)]
-        pub enum c_void {
-            // Two dummy variants so the #[repr] attribute can be used.
-            #[doc(hidden)]
-            __variant1,
-            #[doc(hidden)]
-            __variant2,
-        }
-    }
-}
+pub use ::ffi::c_void;
\ No newline at end of file
diff --git a/src/unix/aix/mod.rs b/src/unix/aix/mod.rs
index c072ae55e5836..ebe81d87c854c 100644
--- a/src/unix/aix/mod.rs
+++ b/src/unix/aix/mod.rs
@@ -534,20 +534,17 @@ s! {
 }
 
 s_no_extra_traits! {
-    #[cfg(libc_union)]
     pub union __sigaction_sa_union {
         pub __su_handler: extern fn(c: ::c_int),
         pub __su_sigaction: extern fn(c: ::c_int, info: *mut siginfo_t, ptr: *mut ::c_void),
     }
 
     pub struct sigaction {
-        #[cfg(libc_union)]
         pub sa_union: __sigaction_sa_union,
         pub sa_mask: sigset_t,
         pub sa_flags: ::c_int,
     }
 
-    #[cfg(libc_union)]
     pub union __poll_ctl_ext_u {
         pub addr: *mut ::c_void,
         pub data32: u32,
@@ -559,7 +556,6 @@ s_no_extra_traits! {
         pub command: u8,
         pub events: ::c_short,
         pub fd: ::c_int,
-        #[cfg(libc_union)]
         pub u: __poll_ctl_ext_u,
         pub reversed64: [u64; 6],
     }
@@ -567,7 +563,6 @@ s_no_extra_traits! {
 
 cfg_if! {
     if #[cfg(feature = "extra_traits")] {
-        #[cfg(libc_union)]
         impl PartialEq for __sigaction_sa_union {
             fn eq(&self, other: &__sigaction_sa_union) -> bool {
                 unsafe {
@@ -576,9 +571,7 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl Eq for __sigaction_sa_union {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __sigaction_sa_union {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("__sigaction_sa_union")
@@ -587,7 +580,6 @@ cfg_if! {
                     .finish()
             }
         }
-        #[cfg(libc_union)]
         impl ::hash::Hash for __sigaction_sa_union {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
@@ -599,20 +591,15 @@ cfg_if! {
 
         impl PartialEq for sigaction {
             fn eq(&self, other: &sigaction) -> bool {
-                #[cfg(libc_union)]
-                let union_eq = self.sa_union == other.sa_union;
-                #[cfg(not(libc_union))]
-                let union_eq = true;
                 self.sa_mask == other.sa_mask
                     && self.sa_flags == other.sa_flags
-                    && union_eq
+                    && self.sa_union == other.sa_union
             }
         }
         impl Eq for sigaction {}
         impl ::fmt::Debug for sigaction {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 let mut struct_formatter = f.debug_struct("sigaction");
-                #[cfg(libc_union)]
                 struct_formatter.field("sa_union", &self.sa_union);
                 struct_formatter.field("sa_mask", &self.sa_mask);
                 struct_formatter.field("sa_flags", &self.sa_flags);
@@ -621,14 +608,12 @@ cfg_if! {
         }
         impl ::hash::Hash for sigaction {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
-                #[cfg(libc_union)]
                 self.sa_union.hash(state);
                 self.sa_mask.hash(state);
                 self.sa_flags.hash(state);
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for __poll_ctl_ext_u {
             fn eq(&self, other: &__poll_ctl_ext_u) -> bool {
                 unsafe {
@@ -638,9 +623,7 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl Eq for __poll_ctl_ext_u {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __poll_ctl_ext_u {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("__poll_ctl_ext_u")
@@ -650,7 +633,6 @@ cfg_if! {
                     .finish()
             }
         }
-        #[cfg(libc_union)]
         impl ::hash::Hash for __poll_ctl_ext_u {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
@@ -663,16 +645,12 @@ cfg_if! {
 
         impl PartialEq for poll_ctl_ext {
             fn eq(&self, other: &poll_ctl_ext) -> bool {
-                #[cfg(libc_union)]
-                let union_eq = self.u == other.u;
-                #[cfg(not(libc_union))]
-                let union_eq = true;
                 self.version == other.version
                     && self.command == other.command
                     && self.events == other.events
                     && self.fd == other.fd
                     && self.reversed64 == other.reversed64
-                    && union_eq
+                    && self.u == other.u
             }
         }
         impl Eq for poll_ctl_ext {}
@@ -683,7 +661,6 @@ cfg_if! {
                 struct_formatter.field("command", &self.command);
                 struct_formatter.field("events", &self.events);
                 struct_formatter.field("fd", &self.fd);
-                #[cfg(libc_union)]
                 struct_formatter.field("u", &self.u);
                 struct_formatter.field("reversed64", &self.reversed64);
                 struct_formatter.finish()
@@ -695,7 +672,6 @@ cfg_if! {
                 self.command.hash(state);
                 self.events.hash(state);
                 self.fd.hash(state);
-                #[cfg(libc_union)]
                 self.u.hash(state);
                 self.reversed64.hash(state);
             }
diff --git a/src/unix/aix/powerpc64.rs b/src/unix/aix/powerpc64.rs
index 2cacf29f6b418..deec291b28dca 100644
--- a/src/unix/aix/powerpc64.rs
+++ b/src/unix/aix/powerpc64.rs
@@ -199,7 +199,6 @@ s_no_extra_traits! {
         pub __pad: [::c_int; 3],
     }
 
-    #[cfg(libc_union)]
     pub union _kernel_simple_lock {
         pub _slock: ::c_long,
         // Should be pointer to 'lock_data_instrumented'
@@ -228,9 +227,7 @@ s_no_extra_traits! {
         pub f_dir_off: ::c_long,
         // Should be pointer to 'cred'
         pub f_cred: *mut ::c_void,
-        #[cfg(libc_union)]
         pub f_lock: _kernel_simple_lock,
-        #[cfg(libc_union)]
         pub f_offset_lock: _kernel_simple_lock,
         pub f_vinfo: ::caddr_t,
         pub f_ops: *mut fileops_t,
@@ -239,7 +236,6 @@ s_no_extra_traits! {
         pub f_fdata: [::c_char; 160],
     }
 
-    #[cfg(libc_union)]
     pub union __ld_info_file {
         pub _ldinfo_fd: ::c_int,
         pub _ldinfo_fp: *mut file,
@@ -249,7 +245,6 @@ s_no_extra_traits! {
     pub struct ld_info {
         pub ldinfo_next: ::c_uint,
         pub ldinfo_flags: ::c_uint,
-        #[cfg(libc_union)]
         pub _file: __ld_info_file,
         pub ldinfo_textorg: *mut ::c_void,
         pub ldinfo_textsize: ::c_ulong,
@@ -258,7 +253,6 @@ s_no_extra_traits! {
         pub ldinfo_filename: [::c_char; 2],
     }
 
-    #[cfg(libc_union)]
     pub union __pollfd_ext_u {
         pub addr: *mut ::c_void,
         pub data32: u32,
@@ -269,7 +263,6 @@ s_no_extra_traits! {
         pub fd: ::c_int,
         pub events: ::c_ushort,
         pub revents: ::c_ushort,
-        #[cfg(libc_union)]
         pub data: __pollfd_ext_u,
     }
 }
@@ -300,10 +293,6 @@ cfg_if! {
     if #[cfg(feature = "extra_traits")] {
         impl PartialEq for siginfo_t {
             fn eq(&self, other: &siginfo_t) -> bool {
-                #[cfg(libc_union)]
-                let value_eq = self.si_value == other.si_value;
-                #[cfg(not(libc_union))]
-                let value_eq = true;
                 self.si_signo == other.si_signo
                     && self.si_errno == other.si_errno
                     && self.si_code == other.si_code
@@ -313,7 +302,7 @@ cfg_if! {
                     && self.si_addr == other.si_addr
                     && self.si_band == other.si_band
                     && self.__si_flags == other.__si_flags
-                    && value_eq
+                    && self.si_value == other.si_value
             }
         }
         impl Eq for siginfo_t {}
@@ -328,7 +317,6 @@ cfg_if! {
                 struct_formatter.field("si_status", &self.si_status);
                 struct_formatter.field("si_addr", &self.si_addr);
                 struct_formatter.field("si_band", &self.si_band);
-                #[cfg(libc_union)]
                 struct_formatter.field("si_value", &self.si_value);
                 struct_formatter.field("__si_flags", &self.__si_flags);
                 struct_formatter.finish()
@@ -344,13 +332,11 @@ cfg_if! {
                 self.si_status.hash(state);
                 self.si_addr.hash(state);
                 self.si_band.hash(state);
-                #[cfg(libc_union)]
                 self.si_value.hash(state);
                 self.__si_flags.hash(state);
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for _kernel_simple_lock {
             fn eq(&self, other: &_kernel_simple_lock) -> bool {
                 unsafe {
@@ -359,9 +345,7 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl Eq for _kernel_simple_lock {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for _kernel_simple_lock {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("_kernel_simple_lock")
@@ -370,7 +354,6 @@ cfg_if! {
                     .finish()
             }
         }
-        #[cfg(libc_union)]
         impl ::hash::Hash for _kernel_simple_lock {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
@@ -413,11 +396,6 @@ cfg_if! {
 
         impl PartialEq for file {
             fn eq(&self, other: &file) -> bool {
-                #[cfg(libc_union)]
-                let lock_eq = self.f_lock == other.f_lock
-                    && self.f_offset_lock == other.f_offset_lock;
-                #[cfg(not(libc_union))]
-                let lock_eq = true;
                 self.f_flag == other.f_flag
                     && self.f_count == other.f_count
                     && self.f_options == other.f_options
@@ -431,7 +409,8 @@ cfg_if! {
                     && self.f_parentp == other.f_parentp
                     && self.f_fnamep == other.f_fnamep
                     && self.f_fdata == other.f_fdata
-                    && lock_eq
+                    && self.f_lock == other.f_lock
+                    && self.f_offset_lock == other.f_offset_lock
             }
         }
         impl Eq for file {}
@@ -446,9 +425,7 @@ cfg_if! {
                 struct_formatter.field("f_offset", &self.f_offset);
                 struct_formatter.field("f_dir_off", &self.f_dir_off);
                 struct_formatter.field("f_cred", &self.f_cred);
-                #[cfg(libc_union)]
                 struct_formatter.field("f_lock", &self.f_lock);
-                #[cfg(libc_union)]
                 struct_formatter.field("f_offset_lock", &self.f_offset_lock);
                 struct_formatter.field("f_vinfo", &self.f_vinfo);
                 struct_formatter.field("f_ops", &self.f_ops);
@@ -468,9 +445,7 @@ cfg_if! {
                 self.f_offset.hash(state);
                 self.f_dir_off.hash(state);
                 self.f_cred.hash(state);
-                #[cfg(libc_union)]
                 self.f_lock.hash(state);
-                #[cfg(libc_union)]
                 self.f_offset_lock.hash(state);
                 self.f_vinfo.hash(state);
                 self.f_ops.hash(state);
@@ -480,7 +455,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for __ld_info_file {
             fn eq(&self, other: &__ld_info_file) -> bool {
                 unsafe {
@@ -490,9 +464,7 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl Eq for __ld_info_file {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __ld_info_file {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("__ld_info_file")
@@ -502,7 +474,6 @@ cfg_if! {
                     .finish()
             }
         }
-        #[cfg(libc_union)]
         impl ::hash::Hash for __ld_info_file {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
@@ -515,10 +486,6 @@ cfg_if! {
 
         impl PartialEq for ld_info {
             fn eq(&self, other: &ld_info) -> bool {
-                #[cfg(libc_union)]
-                let file_eq = self._file == other._file;
-                #[cfg(not(libc_union))]
-                let file_eq = true;
                 self.ldinfo_next == other.ldinfo_next
                     && self.ldinfo_flags == other.ldinfo_flags
                     && self.ldinfo_textorg == other.ldinfo_textorg
@@ -526,7 +493,7 @@ cfg_if! {
                     && self.ldinfo_dataorg == other.ldinfo_dataorg
                     && self.ldinfo_datasize == other.ldinfo_datasize
                     && self.ldinfo_filename == other.ldinfo_filename
-                    && file_eq
+                    && self._file == other._file
             }
         }
         impl Eq for ld_info {}
@@ -540,7 +507,6 @@ cfg_if! {
                 struct_formatter.field("ldinfo_dataorg", &self.ldinfo_dataorg);
                 struct_formatter.field("ldinfo_datasize", &self.ldinfo_datasize);
                 struct_formatter.field("ldinfo_filename", &self.ldinfo_filename);
-                #[cfg(libc_union)]
                 struct_formatter.field("_file", &self._file);
                 struct_formatter.finish()
             }
@@ -554,12 +520,10 @@ cfg_if! {
                 self.ldinfo_dataorg.hash(state);
                 self.ldinfo_datasize.hash(state);
                 self.ldinfo_filename.hash(state);
-                #[cfg(libc_union)]
                 self._file.hash(state);
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for __pollfd_ext_u {
             fn eq(&self, other: &__pollfd_ext_u) -> bool {
                 unsafe {
@@ -569,9 +533,7 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl Eq for __pollfd_ext_u {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __pollfd_ext_u {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("__pollfd_ext_u")
@@ -581,7 +543,6 @@ cfg_if! {
                     .finish()
             }
         }
-        #[cfg(libc_union)]
         impl ::hash::Hash for __pollfd_ext_u {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
@@ -594,14 +555,10 @@ cfg_if! {
 
         impl PartialEq for pollfd_ext {
             fn eq(&self, other: &pollfd_ext) -> bool {
-                #[cfg(libc_union)]
-                let data_eq = self.data == other.data;
-                #[cfg(not(libc_union))]
-                let data_eq = true;
                 self.fd == other.fd
                     && self.events == other.events
                     && self.revents == other.revents
-                    && data_eq
+                    && self.data == other.data
             }
         }
         impl Eq for pollfd_ext {}
@@ -611,7 +568,6 @@ cfg_if! {
                 struct_formatter.field("fd", &self.fd);
                 struct_formatter.field("events", &self.events);
                 struct_formatter.field("revents", &self.revents);
-                #[cfg(libc_union)]
                 struct_formatter.field("data", &self.data);
                 struct_formatter.finish()
             }
@@ -621,7 +577,6 @@ cfg_if! {
                 self.fd.hash(state);
                 self.events.hash(state);
                 self.revents.hash(state);
-                #[cfg(libc_union)]
                 self.data.hash(state);
             }
         }
diff --git a/src/unix/bsd/apple/b32/mod.rs b/src/unix/bsd/apple/b32/mod.rs
index 0f1722f975744..7b817101d50c6 100644
--- a/src/unix/bsd/apple/b32/mod.rs
+++ b/src/unix/bsd/apple/b32/mod.rs
@@ -111,9 +111,6 @@ extern "C" {
     ) -> ::c_int;
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+
+mod align;
+pub use self::align::*;
diff --git a/src/unix/bsd/apple/b64/aarch64/align.rs b/src/unix/bsd/apple/b64/aarch64/align.rs
index 131e15b69ad94..7f86a134649cf 100644
--- a/src/unix/bsd/apple/b64/aarch64/align.rs
+++ b/src/unix/bsd/apple/b64/aarch64/align.rs
@@ -39,16 +39,8 @@ s! {
         pub __pad: u32,
     }
 
-    // This type natively uses a uint128, but for a while we hacked
-    // it in with repr(align) and `[u64; 2]`. uint128 isn't available
-    // all the way back to our earliest supported versions so we
-    // preserver the old shim.
-    #[cfg_attr(not(libc_int128), repr(align(16)))]
     pub struct __darwin_arm_neon_state64 {
-        #[cfg(libc_int128)]
         pub __v: [::__uint128_t; 32],
-        #[cfg(not(libc_int128))]
-        pub __v: [[u64; 2]; 32],
         pub __fpsr: u32,
         pub __fpcr: u32,
     }
diff --git a/src/unix/bsd/apple/b64/aarch64/mod.rs b/src/unix/bsd/apple/b64/aarch64/mod.rs
index 79e9ac842f9ca..a32abf17008fd 100644
--- a/src/unix/bsd/apple/b64/aarch64/mod.rs
+++ b/src/unix/bsd/apple/b64/aarch64/mod.rs
@@ -6,9 +6,5 @@ s! {
     }
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/bsd/apple/b64/x86_64/mod.rs b/src/unix/bsd/apple/b64/x86_64/mod.rs
index 653650c26289f..a15d6cfe47c31 100644
--- a/src/unix/bsd/apple/b64/x86_64/mod.rs
+++ b/src/unix/bsd/apple/b64/x86_64/mod.rs
@@ -172,9 +172,5 @@ s! {
     }
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/bsd/apple/mod.rs b/src/unix/bsd/apple/mod.rs
index 92d724071a3d4..507230ffdcf80 100644
--- a/src/unix/bsd/apple/mod.rs
+++ b/src/unix/bsd/apple/mod.rs
@@ -1140,13 +1140,10 @@ s! {
     #[cfg_attr(libc_packedN, repr(packed(4)))]
     pub struct ifconf {
         pub ifc_len: ::c_int,
-        #[cfg(libc_union)]
         pub ifc_ifcu: __c_anonymous_ifc_ifcu,
-        #[cfg(not(libc_union))]
-        pub ifc_ifcu: *mut ifreq,
     }
 
-    #[cfg_attr(libc_align, repr(align(8)))]
+    #[repr(align(8))]
     pub struct tcp_connection_info {
         pub tcpi_state: u8,
         pub tcpi_snd_wscale: u8,
@@ -1485,7 +1482,6 @@ s_no_extra_traits! {
         pub ifdm_max: ::c_int,
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_ifk_data {
         pub ifk_ptr: *mut ::c_void,
         pub ifk_value: ::c_int,
@@ -1495,11 +1491,9 @@ s_no_extra_traits! {
     pub struct ifkpi {
         pub ifk_module_id: ::c_uint,
         pub ifk_type: ::c_uint,
-        #[cfg(libc_union)]
         pub ifk_data: __c_anonymous_ifk_data,
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_ifr_ifru {
         pub ifru_addr: ::sockaddr,
         pub ifru_dstaddr: ::sockaddr,
@@ -1521,13 +1515,9 @@ s_no_extra_traits! {
 
     pub struct ifreq {
         pub ifr_name: [::c_char; ::IFNAMSIZ],
-        #[cfg(libc_union)]
         pub ifr_ifru: __c_anonymous_ifr_ifru,
-        #[cfg(not(libc_union))]
-        pub ifr_ifru: ::sockaddr,
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_ifc_ifcu {
         pub ifcu_buf: *mut ::c_char,
         pub ifcu_req: *mut ifreq,
@@ -2909,7 +2899,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_ifk_data {
             fn eq(&self, other: &__c_anonymous_ifk_data) -> bool {
                 unsafe {
@@ -2919,10 +2908,8 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_ifk_data {}
 
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_ifk_data {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("__c_anonymous_ifk_data")
@@ -2931,7 +2918,6 @@ cfg_if! {
                     .finish()
             }
         }
-        #[cfg(libc_union)]
         impl ::hash::Hash for __c_anonymous_ifk_data {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
@@ -2966,7 +2952,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_ifr_ifru {
             fn eq(&self, other: &__c_anonymous_ifr_ifru) -> bool {
                 unsafe {
@@ -2990,10 +2975,8 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_ifr_ifru {}
 
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_ifr_ifru {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("__c_anonymous_ifr_ifru")
@@ -3017,7 +3000,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::hash::Hash for __c_anonymous_ifr_ifru {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
@@ -3066,10 +3048,8 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_ifc_ifcu {}
 
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_ifc_ifcu {
             fn eq(&self, other: &__c_anonymous_ifc_ifcu) -> bool {
                 unsafe {
@@ -3079,7 +3059,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_ifc_ifcu {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("ifc_ifcu")
@@ -3089,7 +3068,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::hash::Hash for __c_anonymous_ifc_ifcu {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe { self.ifcu_buf.hash(state) };
@@ -5488,76 +5466,53 @@ cfg_if! {
             const __DARWIN_ALIGNBYTES32: usize = ::mem::size_of::<u32>() - 1;
             p + __DARWIN_ALIGNBYTES32 & !__DARWIN_ALIGNBYTES32
         }
-    } else if #[cfg(libc_const_size_of)] {
-        fn __DARWIN_ALIGN32(p: usize) -> usize {
-            const __DARWIN_ALIGNBYTES32: usize = ::mem::size_of::<u32>() - 1;
-            p + __DARWIN_ALIGNBYTES32 & !__DARWIN_ALIGNBYTES32
-        }
     } else {
         fn __DARWIN_ALIGN32(p: usize) -> usize {
-            let __DARWIN_ALIGNBYTES32: usize = ::mem::size_of::<u32>() - 1;
+            const __DARWIN_ALIGNBYTES32: usize = ::mem::size_of::<u32>() - 1;
             p + __DARWIN_ALIGNBYTES32 & !__DARWIN_ALIGNBYTES32
         }
     }
 }
 
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        pub const THREAD_EXTENDED_POLICY_COUNT: mach_msg_type_number_t =
-            (::mem::size_of::<thread_extended_policy_data_t>() / ::mem::size_of::<integer_t>())
-            as mach_msg_type_number_t;
-        pub const THREAD_TIME_CONSTRAINT_POLICY_COUNT: mach_msg_type_number_t =
-            (::mem::size_of::<thread_time_constraint_policy_data_t>() /
-             ::mem::size_of::<integer_t>()) as mach_msg_type_number_t;
-        pub const THREAD_PRECEDENCE_POLICY_COUNT: mach_msg_type_number_t =
-            (::mem::size_of::<thread_precedence_policy_data_t>() / ::mem::size_of::<integer_t>())
-            as mach_msg_type_number_t;
-        pub const THREAD_AFFINITY_POLICY_COUNT: mach_msg_type_number_t =
-            (::mem::size_of::<thread_affinity_policy_data_t>() / ::mem::size_of::<integer_t>())
-            as mach_msg_type_number_t;
-        pub const THREAD_BACKGROUND_POLICY_COUNT: mach_msg_type_number_t =
-            (::mem::size_of::<thread_background_policy_data_t>() / ::mem::size_of::<integer_t>())
-            as mach_msg_type_number_t;
-        pub const THREAD_LATENCY_QOS_POLICY_COUNT: mach_msg_type_number_t =
-            (::mem::size_of::<thread_latency_qos_policy_data_t>() / ::mem::size_of::<integer_t>())
-            as mach_msg_type_number_t;
-        pub const THREAD_THROUGHPUT_QOS_POLICY_COUNT: mach_msg_type_number_t =
-            (::mem::size_of::<thread_throughput_qos_policy_data_t>() /
-             ::mem::size_of::<integer_t>()) as mach_msg_type_number_t;
-        pub const THREAD_BASIC_INFO_COUNT: mach_msg_type_number_t =
-            (::mem::size_of::<thread_basic_info_data_t>() / ::mem::size_of::<integer_t>())
-            as mach_msg_type_number_t;
-        pub const THREAD_IDENTIFIER_INFO_COUNT: mach_msg_type_number_t =
-            (::mem::size_of::<thread_identifier_info_data_t>() / ::mem::size_of::<integer_t>())
-            as mach_msg_type_number_t;
-        pub const THREAD_EXTENDED_INFO_COUNT: mach_msg_type_number_t =
-            (::mem::size_of::<thread_extended_info_data_t>() / ::mem::size_of::<integer_t>())
-            as mach_msg_type_number_t;
-
-        pub const TASK_THREAD_TIMES_INFO_COUNT: u32 =
-            (::mem::size_of::<task_thread_times_info_data_t>()
-            / ::mem::size_of::<natural_t>()) as u32;
-        pub const MACH_TASK_BASIC_INFO_COUNT: u32 = (::mem::size_of::<mach_task_basic_info_data_t>()
-            / ::mem::size_of::<natural_t>()) as u32;
-        pub const HOST_VM_INFO64_COUNT: mach_msg_type_number_t =
-            (::mem::size_of::<vm_statistics64_data_t>() / ::mem::size_of::<integer_t>())
-            as mach_msg_type_number_t;
-    } else {
-        pub const THREAD_EXTENDED_POLICY_COUNT: mach_msg_type_number_t = 1;
-        pub const THREAD_TIME_CONSTRAINT_POLICY_COUNT: mach_msg_type_number_t = 4;
-        pub const THREAD_PRECEDENCE_POLICY_COUNT: mach_msg_type_number_t = 1;
-        pub const THREAD_AFFINITY_POLICY_COUNT: mach_msg_type_number_t = 1;
-        pub const THREAD_BACKGROUND_POLICY_COUNT: mach_msg_type_number_t = 1;
-        pub const THREAD_LATENCY_QOS_POLICY_COUNT: mach_msg_type_number_t = 1;
-        pub const THREAD_THROUGHPUT_QOS_POLICY_COUNT: mach_msg_type_number_t = 1;
-        pub const THREAD_BASIC_INFO_COUNT: mach_msg_type_number_t = 10;
-        pub const THREAD_IDENTIFIER_INFO_COUNT: mach_msg_type_number_t = 6;
-        pub const THREAD_EXTENDED_INFO_COUNT: mach_msg_type_number_t = 28;
-        pub const TASK_THREAD_TIMES_INFO_COUNT: u32 = 4;
-        pub const MACH_TASK_BASIC_INFO_COUNT: u32 = 12;
-        pub const HOST_VM_INFO64_COUNT: mach_msg_type_number_t = 38;
-    }
-}
+pub const THREAD_EXTENDED_POLICY_COUNT: mach_msg_type_number_t =
+    (::mem::size_of::<thread_extended_policy_data_t>() / ::mem::size_of::<integer_t>())
+    as mach_msg_type_number_t;
+pub const THREAD_TIME_CONSTRAINT_POLICY_COUNT: mach_msg_type_number_t =
+    (::mem::size_of::<thread_time_constraint_policy_data_t>() /
+        ::mem::size_of::<integer_t>()) as mach_msg_type_number_t;
+pub const THREAD_PRECEDENCE_POLICY_COUNT: mach_msg_type_number_t =
+    (::mem::size_of::<thread_precedence_policy_data_t>() / ::mem::size_of::<integer_t>())
+    as mach_msg_type_number_t;
+pub const THREAD_AFFINITY_POLICY_COUNT: mach_msg_type_number_t =
+    (::mem::size_of::<thread_affinity_policy_data_t>() / ::mem::size_of::<integer_t>())
+    as mach_msg_type_number_t;
+pub const THREAD_BACKGROUND_POLICY_COUNT: mach_msg_type_number_t =
+    (::mem::size_of::<thread_background_policy_data_t>() / ::mem::size_of::<integer_t>())
+    as mach_msg_type_number_t;
+pub const THREAD_LATENCY_QOS_POLICY_COUNT: mach_msg_type_number_t =
+    (::mem::size_of::<thread_latency_qos_policy_data_t>() / ::mem::size_of::<integer_t>())
+    as mach_msg_type_number_t;
+pub const THREAD_THROUGHPUT_QOS_POLICY_COUNT: mach_msg_type_number_t =
+    (::mem::size_of::<thread_throughput_qos_policy_data_t>() /
+        ::mem::size_of::<integer_t>()) as mach_msg_type_number_t;
+pub const THREAD_BASIC_INFO_COUNT: mach_msg_type_number_t =
+    (::mem::size_of::<thread_basic_info_data_t>() / ::mem::size_of::<integer_t>())
+    as mach_msg_type_number_t;
+pub const THREAD_IDENTIFIER_INFO_COUNT: mach_msg_type_number_t =
+    (::mem::size_of::<thread_identifier_info_data_t>() / ::mem::size_of::<integer_t>())
+    as mach_msg_type_number_t;
+pub const THREAD_EXTENDED_INFO_COUNT: mach_msg_type_number_t =
+    (::mem::size_of::<thread_extended_info_data_t>() / ::mem::size_of::<integer_t>())
+    as mach_msg_type_number_t;
+
+pub const TASK_THREAD_TIMES_INFO_COUNT: u32 =
+    (::mem::size_of::<task_thread_times_info_data_t>()
+    / ::mem::size_of::<natural_t>()) as u32;
+pub const MACH_TASK_BASIC_INFO_COUNT: u32 = (::mem::size_of::<mach_task_basic_info_data_t>()
+    / ::mem::size_of::<natural_t>()) as u32;
+pub const HOST_VM_INFO64_COUNT: mach_msg_type_number_t =
+    (::mem::size_of::<vm_statistics64_data_t>() / ::mem::size_of::<integer_t>())
+    as mach_msg_type_number_t;
 
 f! {
     pub fn CMSG_NXTHDR(mhdr: *const ::msghdr,
diff --git a/src/unix/bsd/freebsdlike/freebsd/aarch64.rs b/src/unix/bsd/freebsdlike/freebsd/aarch64.rs
index e8be8815c028e..d240eb001ad5d 100644
--- a/src/unix/bsd/freebsdlike/freebsd/aarch64.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/aarch64.rs
@@ -33,16 +33,7 @@ s_no_extra_traits! {
     }
 }
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_longlong>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 8 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_longlong>() - 1;
 
 cfg_if! {
     if #[cfg(feature = "extra_traits")] {
diff --git a/src/unix/bsd/freebsdlike/freebsd/arm.rs b/src/unix/bsd/freebsdlike/freebsd/arm.rs
index 300b3dd45ca9d..af3c8a7cf6f6c 100644
--- a/src/unix/bsd/freebsdlike/freebsd/arm.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/arm.rs
@@ -36,15 +36,6 @@ s! {
     }
 }
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_int>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 4 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_int>() - 1;
 pub const MAP_32BIT: ::c_int = 0x00080000;
 pub const MINSIGSTKSZ: ::size_t = 4096; // 1024 * 4
diff --git a/src/unix/bsd/freebsdlike/freebsd/mod.rs b/src/unix/bsd/freebsdlike/freebsd/mod.rs
index 47b4bd36e6d02..13ac54a432968 100644
--- a/src/unix/bsd/freebsdlike/freebsd/mod.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/mod.rs
@@ -971,10 +971,7 @@ s! {
 
     pub struct ifconf {
         pub ifc_len: ::c_int,
-        #[cfg(libc_union)]
         pub ifc_ifcu: __c_anonymous_ifc_ifcu,
-        #[cfg(not(libc_union))]
-        pub ifc_ifcu: *mut ifreq,
     }
 
     pub struct au_mask_t {
@@ -1359,7 +1356,6 @@ s_no_extra_traits! {
         pub __ut_spare: [::c_char; 64],
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_cr_pid {
         __cr_unused: *mut ::c_void,
         pub cr_pid: ::pid_t,
@@ -1370,10 +1366,7 @@ s_no_extra_traits! {
         pub cr_uid: ::uid_t,
         pub cr_ngroups: ::c_short,
         pub cr_groups: [::gid_t; 16],
-        #[cfg(libc_union)]
         pub cr_pid__c_anonymous_union: __c_anonymous_cr_pid,
-        #[cfg(not(libc_union))]
-        __cr_unused1: *mut ::c_void,
     }
 
     pub struct sockaddr_dl {
@@ -1415,24 +1408,20 @@ s_no_extra_traits! {
         pub devname: [::c_char; SPECNAMELEN as usize + 1],
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_elf32_auxv_union {
         pub a_val: ::c_int,
     }
 
     pub struct Elf32_Auxinfo {
         pub a_type: ::c_int,
-        #[cfg(libc_union)]
         pub a_un: __c_anonymous_elf32_auxv_union,
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_ifi_epoch {
         pub tt: ::time_t,
         pub ph: u64,
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_ifi_lastchange {
         pub tv: ::timeval,
         pub ph: __c_anonymous_ph,
@@ -1486,20 +1475,11 @@ s_no_extra_traits! {
         /// HW offload capabilities, see IFCAP
         pub ifi_hwassist: u64,
         /// uptime at attach or stat reset
-        #[cfg(libc_union)]
         pub __ifi_epoch: __c_anonymous_ifi_epoch,
-        /// uptime at attach or stat reset
-        #[cfg(not(libc_union))]
-        pub __ifi_epoch: u64,
         /// time of last administrative change
-        #[cfg(libc_union)]
         pub __ifi_lastchange: __c_anonymous_ifi_lastchange,
-        /// time of last administrative change
-        #[cfg(not(libc_union))]
-        pub __ifi_lastchange: ::timeval,
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_ifr_ifru {
         pub ifru_addr: ::sockaddr,
         pub ifru_dstaddr: ::sockaddr,
@@ -1521,13 +1501,9 @@ s_no_extra_traits! {
     pub struct ifreq {
         /// if name, e.g. "en0"
         pub ifr_name: [::c_char; ::IFNAMSIZ],
-        #[cfg(libc_union)]
         pub ifr_ifru: __c_anonymous_ifr_ifru,
-        #[cfg(not(libc_union))]
-        pub ifr_ifru: ::sockaddr,
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_ifc_ifcu {
         pub ifcu_buf: ::caddr_t,
         pub ifcu_req: *mut ifreq,
@@ -1706,15 +1682,12 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_cr_pid {
             fn eq(&self, other: &__c_anonymous_cr_pid) -> bool {
                 unsafe { self.cr_pid == other.cr_pid}
             }
         }
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_cr_pid {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_cr_pid {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("cr_pid")
@@ -1722,7 +1695,6 @@ cfg_if! {
                     .finish()
             }
         }
-        #[cfg(libc_union)]
         impl ::hash::Hash for __c_anonymous_cr_pid {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe { self.cr_pid.hash(state) };
@@ -1731,17 +1703,12 @@ cfg_if! {
 
         impl PartialEq for xucred {
             fn eq(&self, other: &xucred) -> bool {
-                #[cfg(libc_union)]
-                let equal_cr_pid = self.cr_pid__c_anonymous_union
-                    == other.cr_pid__c_anonymous_union;
-                #[cfg(not(libc_union))]
-                let equal_cr_pid = self.__cr_unused1 == other.__cr_unused1;
-
                 self.cr_version == other.cr_version
                     && self.cr_uid == other.cr_uid
                     && self.cr_ngroups == other.cr_ngroups
                     && self.cr_groups == other.cr_groups
-                    && equal_cr_pid
+                    && self.cr_pid__c_anonymous_union
+                    == other.cr_pid__c_anonymous_union
             }
         }
         impl Eq for xucred {}
@@ -1752,7 +1719,6 @@ cfg_if! {
                 struct_formatter.field("cr_uid", &self.cr_uid);
                 struct_formatter.field("cr_ngroups", &self.cr_ngroups);
                 struct_formatter.field("cr_groups", &self.cr_groups);
-                #[cfg(libc_union)]
                 struct_formatter.field(
                     "cr_pid__c_anonymous_union",
                     &self.cr_pid__c_anonymous_union
@@ -1766,10 +1732,7 @@ cfg_if! {
                 self.cr_uid.hash(state);
                 self.cr_ngroups.hash(state);
                 self.cr_groups.hash(state);
-                #[cfg(libc_union)]
                 self.cr_pid__c_anonymous_union.hash(state);
-                #[cfg(not(libc_union))]
-                self.__cr_unused1.hash(state);
             }
         }
 
@@ -1903,15 +1866,12 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_elf32_auxv_union {
             fn eq(&self, other: &__c_anonymous_elf32_auxv_union) -> bool {
                 unsafe { self.a_val == other.a_val}
             }
         }
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_elf32_auxv_union {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_elf32_auxv_union {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("a_val")
@@ -1919,13 +1879,6 @@ cfg_if! {
                     .finish()
             }
         }
-        #[cfg(not(libc_union))]
-        impl PartialEq for Elf32_Auxinfo {
-            fn eq(&self, other: &Elf32_Auxinfo) -> bool {
-                self.a_type == other.a_type
-            }
-        }
-        #[cfg(libc_union)]
         impl PartialEq for Elf32_Auxinfo {
             fn eq(&self, other: &Elf32_Auxinfo) -> bool {
                 self.a_type == other.a_type
@@ -1933,15 +1886,6 @@ cfg_if! {
             }
         }
         impl Eq for Elf32_Auxinfo {}
-        #[cfg(not(libc_union))]
-        impl ::fmt::Debug for Elf32_Auxinfo {
-            fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
-                f.debug_struct("Elf32_Auxinfo")
-                    .field("a_type", &self.a_type)
-                    .finish()
-            }
-        }
-        #[cfg(libc_union)]
         impl ::fmt::Debug for Elf32_Auxinfo {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("Elf32_Auxinfo")
@@ -1951,7 +1895,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_ifr_ifru {
             fn eq(&self, other: &__c_anonymous_ifr_ifru) -> bool {
                 unsafe {
@@ -1973,9 +1916,7 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_ifr_ifru {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_ifr_ifru {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("ifr_ifru")
@@ -1997,7 +1938,6 @@ cfg_if! {
                     .finish()
             }
         }
-        #[cfg(libc_union)]
         impl ::hash::Hash for __c_anonymous_ifr_ifru {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe { self.ifru_addr.hash(state) };
@@ -2039,10 +1979,8 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_ifc_ifcu {}
 
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_ifc_ifcu {
             fn eq(&self, other: &__c_anonymous_ifc_ifcu) -> bool {
                 unsafe {
@@ -2052,7 +1990,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_ifc_ifcu {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("ifc_ifcu")
@@ -2062,7 +1999,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::hash::Hash for __c_anonymous_ifc_ifcu {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe { self.ifcu_buf.hash(state) };
@@ -2165,7 +2101,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_ifi_epoch {
             fn eq(&self, other: &__c_anonymous_ifi_epoch) -> bool {
                 unsafe {
@@ -2174,9 +2109,7 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_ifi_epoch {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_ifi_epoch {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("__c_anonymous_ifi_epoch")
@@ -2185,7 +2118,6 @@ cfg_if! {
                     .finish()
             }
         }
-        #[cfg(libc_union)]
         impl ::hash::Hash for __c_anonymous_ifi_epoch {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
@@ -2195,7 +2127,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_ifi_lastchange {
             fn eq(&self, other: &__c_anonymous_ifi_lastchange) -> bool {
                 unsafe {
@@ -2204,9 +2135,7 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_ifi_lastchange {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_ifi_lastchange {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("__c_anonymous_ifi_lastchange")
@@ -2215,7 +2144,6 @@ cfg_if! {
                     .finish()
             }
         }
-        #[cfg(libc_union)]
         impl ::hash::Hash for __c_anonymous_ifi_lastchange {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
diff --git a/src/unix/bsd/freebsdlike/freebsd/powerpc.rs b/src/unix/bsd/freebsdlike/freebsd/powerpc.rs
index a0120c337e0ad..e38f88dc77fbc 100644
--- a/src/unix/bsd/freebsdlike/freebsd/powerpc.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/powerpc.rs
@@ -32,16 +32,7 @@ s! {
     }
 }
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_int>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 4 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_int>() - 1;
 
 pub const MAP_32BIT: ::c_int = 0x00080000;
 pub const MINSIGSTKSZ: ::size_t = 2048; // 512 * 4
diff --git a/src/unix/bsd/freebsdlike/freebsd/powerpc64.rs b/src/unix/bsd/freebsdlike/freebsd/powerpc64.rs
index 7f5b9752264e3..07f2f11cdc9a4 100644
--- a/src/unix/bsd/freebsdlike/freebsd/powerpc64.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/powerpc64.rs
@@ -32,16 +32,7 @@ s! {
     }
 }
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 8 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
 
 pub const MAP_32BIT: ::c_int = 0x00080000;
 pub const MINSIGSTKSZ: ::size_t = 2048; // 512 * 4
diff --git a/src/unix/bsd/freebsdlike/freebsd/riscv64.rs b/src/unix/bsd/freebsdlike/freebsd/riscv64.rs
index f9fa1c2750b22..c5ea8ee203a72 100644
--- a/src/unix/bsd/freebsdlike/freebsd/riscv64.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/riscv64.rs
@@ -35,16 +35,7 @@ s_no_extra_traits! {
     }
 }
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_longlong>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 8 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_longlong>() - 1;
 
 cfg_if! {
     if #[cfg(feature = "extra_traits")] {
diff --git a/src/unix/bsd/freebsdlike/freebsd/x86.rs b/src/unix/bsd/freebsdlike/freebsd/x86.rs
index c3c576ed66681..bbb1127263eff 100644
--- a/src/unix/bsd/freebsdlike/freebsd/x86.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/x86.rs
@@ -77,16 +77,8 @@ s! {
     }
 }
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 4 - 1;
-    }
-}
+
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
 
 cfg_if! {
     if #[cfg(feature = "extra_traits")] {
diff --git a/src/unix/bsd/freebsdlike/freebsd/x86_64/mod.rs b/src/unix/bsd/freebsdlike/freebsd/x86_64/mod.rs
index fb4597927f3d6..c24e304542dbf 100644
--- a/src/unix/bsd/freebsdlike/freebsd/x86_64/mod.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/x86_64/mod.rs
@@ -81,7 +81,6 @@ s_no_extra_traits! {
         pub xmm_pad: [u8; 224],
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_elf64_auxv_union {
         pub a_val: ::c_long,
         pub a_ptr: *mut ::c_void,
@@ -90,7 +89,6 @@ s_no_extra_traits! {
 
     pub struct Elf64_Auxinfo {
         pub a_type: ::c_long,
-        #[cfg(libc_union)]
         pub a_un: __c_anonymous_elf64_auxv_union,
     }
 }
@@ -187,7 +185,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_elf64_auxv_union {
             fn eq(&self, other: &__c_anonymous_elf64_auxv_union) -> bool {
                 unsafe { self.a_val == other.a_val
@@ -195,9 +192,7 @@ cfg_if! {
                         || self.a_fcn == other.a_fcn }
             }
         }
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_elf64_auxv_union {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_elf64_auxv_union {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("a_val")
@@ -205,13 +200,6 @@ cfg_if! {
                     .finish()
             }
         }
-        #[cfg(not(libc_union))]
-        impl PartialEq for Elf64_Auxinfo {
-            fn eq(&self, other: &Elf64_Auxinfo) -> bool {
-                self.a_type == other.a_type
-            }
-        }
-        #[cfg(libc_union)]
         impl PartialEq for Elf64_Auxinfo {
             fn eq(&self, other: &Elf64_Auxinfo) -> bool {
                 self.a_type == other.a_type
@@ -219,15 +207,6 @@ cfg_if! {
             }
         }
         impl Eq for Elf64_Auxinfo {}
-        #[cfg(not(libc_union))]
-        impl ::fmt::Debug for Elf64_Auxinfo {
-            fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
-                f.debug_struct("Elf64_Auxinfo")
-                    .field("a_type", &self.a_type)
-                    .finish()
-            }
-        }
-        #[cfg(libc_union)]
         impl ::fmt::Debug for Elf64_Auxinfo {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("Elf64_Auxinfo")
@@ -239,16 +218,8 @@ cfg_if! {
     }
 }
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 8 - 1;
-    }
-}
+
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
 pub const MAP_32BIT: ::c_int = 0x00080000;
 pub const MINSIGSTKSZ: ::size_t = 2048; // 512 * 4
 
@@ -265,9 +236,5 @@ pub const _MC_FPOWNED_PCB: c_long = 0x20002;
 
 pub const KINFO_FILE_SIZE: ::c_int = 1392;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/bsd/freebsdlike/mod.rs b/src/unix/bsd/freebsdlike/mod.rs
index e0a0fbd01443f..f5780f322c847 100644
--- a/src/unix/bsd/freebsdlike/mod.rs
+++ b/src/unix/bsd/freebsdlike/mod.rs
@@ -432,15 +432,7 @@ cfg_if! {
 }
 
 // Non-public helper constant
-cfg_if! {
-    if #[cfg(all(not(libc_const_size_of), target_pointer_width = "32"))] {
-        const SIZEOF_LONG: usize = 4;
-    } else if #[cfg(all(not(libc_const_size_of), target_pointer_width = "64"))] {
-        const SIZEOF_LONG: usize = 8;
-    } else if #[cfg(libc_const_size_of)] {
-        const SIZEOF_LONG: usize = ::mem::size_of::<::c_long>();
-    }
-}
+const SIZEOF_LONG: usize = ::mem::size_of::<::c_long>();
 
 #[deprecated(
     since = "0.2.64",
diff --git a/src/unix/bsd/netbsdlike/netbsd/aarch64.rs b/src/unix/bsd/netbsdlike/netbsd/aarch64.rs
index 45bca4778c20c..c22ea3d225c8a 100644
--- a/src/unix/bsd/netbsdlike/netbsd/aarch64.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/aarch64.rs
@@ -8,7 +8,6 @@ pub type __cpu_simple_lock_nv_t = ::c_uchar;
 
 s! {
     pub struct __fregset {
-        #[cfg(libc_union)]
         pub __qregs: [__c_anonymous__freg; 32],
         pub __fpcr: u32,
         pub __fpsr: u32,
@@ -30,7 +29,6 @@ s! {
 }
 
 s_no_extra_traits! {
-    #[cfg(libc_union)]
     #[repr(align(16))]
     pub union __c_anonymous__freg {
         pub __b8: [u8; 16],
@@ -43,7 +41,6 @@ s_no_extra_traits! {
 
 cfg_if! {
     if #[cfg(feature = "extra_traits")] {
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous__freg {
             fn eq(&self, other: &__c_anonymous__freg) -> bool {
                 unsafe {
@@ -55,9 +52,7 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous__freg {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous__freg {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 unsafe {
@@ -71,7 +66,6 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl ::hash::Hash for __c_anonymous__freg {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
@@ -86,16 +80,8 @@ cfg_if! {
     }
 }
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_int>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 4 - 1;
-    }
-}
+
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_int>() - 1;
 
 pub const PT_GETREGS: ::c_int = PT_FIRSTMACH + 0;
 pub const PT_SETREGS: ::c_int = PT_FIRSTMACH + 1;
diff --git a/src/unix/bsd/netbsdlike/netbsd/arm.rs b/src/unix/bsd/netbsdlike/netbsd/arm.rs
index b5000d34d66fb..2da780ec6ddcb 100644
--- a/src/unix/bsd/netbsdlike/netbsd/arm.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/arm.rs
@@ -5,16 +5,7 @@ pub type c_ulong = u32;
 pub type c_char = u8;
 pub type __cpu_simple_lock_nv_t = ::c_int;
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_longlong>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 8 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_longlong>() - 1;
 
 pub const PT_GETREGS: ::c_int = PT_FIRSTMACH + 1;
 pub const PT_SETREGS: ::c_int = PT_FIRSTMACH + 2;
diff --git a/src/unix/bsd/netbsdlike/netbsd/mips.rs b/src/unix/bsd/netbsdlike/netbsd/mips.rs
index a536254ceb4b3..c25407fd97393 100644
--- a/src/unix/bsd/netbsdlike/netbsd/mips.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/mips.rs
@@ -5,15 +5,7 @@ pub type c_ulong = u32;
 pub type c_char = i8;
 pub type __cpu_simple_lock_nv_t = ::c_int;
 
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-         #[doc(hidden)]
-         pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_longlong>() - 1;
-    } else {
-         #[doc(hidden)]
-         pub const _ALIGNBYTES: usize = 8 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_longlong>() - 1;
 
 pub const PT_GETREGS: ::c_int = PT_FIRSTMACH + 1;
 pub const PT_SETREGS: ::c_int = PT_FIRSTMACH + 2;
diff --git a/src/unix/bsd/netbsdlike/netbsd/mod.rs b/src/unix/bsd/netbsdlike/netbsd/mod.rs
index 0517a47b69c30..7efe0c85418dc 100644
--- a/src/unix/bsd/netbsdlike/netbsd/mod.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/mod.rs
@@ -688,14 +688,12 @@ s! {
     pub struct posix_spawn_file_actions_entry_t {
         pub fae_action: fae_action,
         pub fae_fildes: ::c_int,
-        #[cfg(libc_union)]
         pub fae_data: __c_anonymous_posix_spawn_fae,
     }
 
     pub struct posix_spawn_file_actions_t {
         pub size: ::c_uint,
         pub len: ::c_uint,
-        #[cfg(libc_union)]
         pub fae: *mut posix_spawn_file_actions_entry_t,
     }
 
@@ -734,7 +732,6 @@ s! {
 
     pub struct ifconf {
         pub ifc_len: ::c_int,
-        #[cfg(libc_union)]
         pub ifc_ifcu: __c_anonymous_ifc_ifcu,
     }
 
@@ -893,13 +890,11 @@ s_no_extra_traits! {
         pub sigev_notify_attributes: *mut ::c_void
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_posix_spawn_fae {
         pub open: __c_anonymous_posix_spawn_fae_open,
         pub dup2: __c_anonymous_posix_spawn_fae_dup2,
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_ifc_ifcu {
         pub ifcu_buf: *mut ::c_void,
         pub ifcu_req: *mut ifreq,
@@ -1332,10 +1327,8 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_posix_spawn_fae {}
 
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_posix_spawn_fae {
             fn eq(&self, other: &__c_anonymous_posix_spawn_fae) -> bool {
                 unsafe {
@@ -1345,7 +1338,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_posix_spawn_fae {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 unsafe {
@@ -1357,7 +1349,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::hash::Hash for __c_anonymous_posix_spawn_fae {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
@@ -1367,10 +1358,8 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_ifc_ifcu {}
 
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_ifc_ifcu {
             fn eq(&self, other: &__c_anonymous_ifc_ifcu) -> bool {
                 unsafe {
@@ -1380,7 +1369,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_ifc_ifcu {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 unsafe {
@@ -1392,7 +1380,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::hash::Hash for __c_anonymous_ifc_ifcu {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
diff --git a/src/unix/bsd/netbsdlike/netbsd/powerpc.rs b/src/unix/bsd/netbsdlike/netbsd/powerpc.rs
index e12fd5e112332..b4bfacf6a0185 100644
--- a/src/unix/bsd/netbsdlike/netbsd/powerpc.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/powerpc.rs
@@ -5,16 +5,7 @@ pub type c_ulong = u32;
 pub type c_char = u8;
 pub type __cpu_simple_lock_nv_t = ::c_int;
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_double>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 8 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_double>() - 1;
 
 pub const PT_STEP: ::c_int = PT_FIRSTMACH + 0;
 pub const PT_GETREGS: ::c_int = PT_FIRSTMACH + 1;
diff --git a/src/unix/bsd/netbsdlike/netbsd/riscv64.rs b/src/unix/bsd/netbsdlike/netbsd/riscv64.rs
index bc09149efeabd..643940d03de85 100644
--- a/src/unix/bsd/netbsdlike/netbsd/riscv64.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/riscv64.rs
@@ -5,15 +5,7 @@ pub type c_ulong = u64;
 pub type c_char = u8;
 pub type __cpu_simple_lock_nv_t = ::c_int;
 
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 8 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
 
 pub const PT_GETREGS: ::c_int = PT_FIRSTMACH + 0;
 pub const PT_SETREGS: ::c_int = PT_FIRSTMACH + 1;
diff --git a/src/unix/bsd/netbsdlike/netbsd/x86.rs b/src/unix/bsd/netbsdlike/netbsd/x86.rs
index daa89a11a67cb..e649c822ed004 100644
--- a/src/unix/bsd/netbsdlike/netbsd/x86.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/x86.rs
@@ -3,13 +3,4 @@ pub type c_ulong = u32;
 pub type c_char = i8;
 pub type __cpu_simple_lock_nv_t = ::c_uchar;
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_int>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 4 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_int>() - 1;
\ No newline at end of file
diff --git a/src/unix/bsd/netbsdlike/netbsd/x86_64.rs b/src/unix/bsd/netbsdlike/netbsd/x86_64.rs
index ba259074f6129..a2087c34e43ef 100644
--- a/src/unix/bsd/netbsdlike/netbsd/x86_64.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/x86_64.rs
@@ -22,16 +22,7 @@ s! {
     }
 }
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 8 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
 
 pub const PT_STEP: ::c_int = PT_FIRSTMACH + 0;
 pub const PT_GETREGS: ::c_int = PT_FIRSTMACH + 1;
diff --git a/src/unix/bsd/netbsdlike/openbsd/aarch64.rs b/src/unix/bsd/netbsdlike/openbsd/aarch64.rs
index 2bc82e486c596..f2159c4dc2142 100644
--- a/src/unix/bsd/netbsdlike/openbsd/aarch64.rs
+++ b/src/unix/bsd/netbsdlike/openbsd/aarch64.rs
@@ -16,15 +16,6 @@ s! {
     }
 }
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 8 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
 
 pub const _MAX_PAGE_SHIFT: u32 = 12;
diff --git a/src/unix/bsd/netbsdlike/openbsd/arm.rs b/src/unix/bsd/netbsdlike/openbsd/arm.rs
index f1ab365d1cd1b..6394df9300245 100644
--- a/src/unix/bsd/netbsdlike/openbsd/arm.rs
+++ b/src/unix/bsd/netbsdlike/openbsd/arm.rs
@@ -2,15 +2,6 @@ pub type c_long = i32;
 pub type c_ulong = u32;
 pub type c_char = u8;
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_double>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 8 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_double>() - 1;
 
 pub const _MAX_PAGE_SHIFT: u32 = 12;
diff --git a/src/unix/bsd/netbsdlike/openbsd/mod.rs b/src/unix/bsd/netbsdlike/openbsd/mod.rs
index 8f470aff9a357..e1fe8ee6f1c3b 100644
--- a/src/unix/bsd/netbsdlike/openbsd/mod.rs
+++ b/src/unix/bsd/netbsdlike/openbsd/mod.rs
@@ -540,10 +540,7 @@ s! {
 
     pub struct ifreq {
         pub ifr_name: [::c_char; ::IFNAMSIZ],
-        #[cfg(libc_union)]
         pub ifr_ifru: __c_anonymous_ifr_ifru,
-        #[cfg(not(libc_union))]
-        pub ifr_ifru: ::sockaddr,
     }
 
     pub struct tcp_info {
@@ -716,7 +713,6 @@ s_no_extra_traits! {
         align: [::c_char; 160],
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_ifr_ifru {
         pub ifru_addr: ::sockaddr,
         pub ifru_dstaddr: ::sockaddr,
@@ -935,7 +931,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_ifr_ifru {
             fn eq(&self, other: &__c_anonymous_ifr_ifru) -> bool {
                 unsafe {
@@ -952,10 +947,8 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_ifr_ifru {}
 
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_ifr_ifru {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("__c_anonymous_ifr_ifru")
@@ -972,7 +965,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::hash::Hash for __c_anonymous_ifr_ifru {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
diff --git a/src/unix/bsd/netbsdlike/openbsd/powerpc.rs b/src/unix/bsd/netbsdlike/openbsd/powerpc.rs
index f1ab365d1cd1b..6394df9300245 100644
--- a/src/unix/bsd/netbsdlike/openbsd/powerpc.rs
+++ b/src/unix/bsd/netbsdlike/openbsd/powerpc.rs
@@ -2,15 +2,6 @@ pub type c_long = i32;
 pub type c_ulong = u32;
 pub type c_char = u8;
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_double>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 8 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_double>() - 1;
 
 pub const _MAX_PAGE_SHIFT: u32 = 12;
diff --git a/src/unix/bsd/netbsdlike/openbsd/powerpc64.rs b/src/unix/bsd/netbsdlike/openbsd/powerpc64.rs
index 99350ec8dc3d4..df0cdd6d1ac53 100644
--- a/src/unix/bsd/netbsdlike/openbsd/powerpc64.rs
+++ b/src/unix/bsd/netbsdlike/openbsd/powerpc64.rs
@@ -2,15 +2,6 @@ pub type c_long = i64;
 pub type c_ulong = u64;
 pub type c_char = u8;
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 8 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
 
 pub const _MAX_PAGE_SHIFT: u32 = 12;
diff --git a/src/unix/bsd/netbsdlike/openbsd/riscv64.rs b/src/unix/bsd/netbsdlike/openbsd/riscv64.rs
index 35f1672bbec9e..fbcc5a76bbed3 100644
--- a/src/unix/bsd/netbsdlike/openbsd/riscv64.rs
+++ b/src/unix/bsd/netbsdlike/openbsd/riscv64.rs
@@ -21,15 +21,6 @@ s! {
     }
 }
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 8 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
 
 pub const _MAX_PAGE_SHIFT: u32 = 12;
diff --git a/src/unix/bsd/netbsdlike/openbsd/x86.rs b/src/unix/bsd/netbsdlike/openbsd/x86.rs
index e87d0ff1e7d5d..a12107bc2a482 100644
--- a/src/unix/bsd/netbsdlike/openbsd/x86.rs
+++ b/src/unix/bsd/netbsdlike/openbsd/x86.rs
@@ -2,15 +2,6 @@ pub type c_long = i32;
 pub type c_ulong = u32;
 pub type c_char = i8;
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_int>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 4 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_int>() - 1;
 
 pub const _MAX_PAGE_SHIFT: u32 = 12;
diff --git a/src/unix/bsd/netbsdlike/openbsd/x86_64.rs b/src/unix/bsd/netbsdlike/openbsd/x86_64.rs
index 60dab004456fc..5cc7dc1fc060f 100644
--- a/src/unix/bsd/netbsdlike/openbsd/x86_64.rs
+++ b/src/unix/bsd/netbsdlike/openbsd/x86_64.rs
@@ -110,16 +110,7 @@ cfg_if! {
     }
 }
 
-// should be pub(crate), but that requires Rust 1.18.0
-cfg_if! {
-    if #[cfg(libc_const_size_of)] {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
-    } else {
-        #[doc(hidden)]
-        pub const _ALIGNBYTES: usize = 8 - 1;
-    }
-}
+pub(crate) const _ALIGNBYTES: usize = ::mem::size_of::<::c_long>() - 1;
 
 pub const _MAX_PAGE_SHIFT: u32 = 12;
 
diff --git a/src/unix/haiku/native.rs b/src/unix/haiku/native.rs
index 85865ad24cea6..5ddfc66e4e209 100644
--- a/src/unix/haiku/native.rs
+++ b/src/unix/haiku/native.rs
@@ -460,7 +460,6 @@ s! {
 }
 
 s_no_extra_traits! {
-    #[cfg(libc_union)]
     pub union cpuid_info {
         pub eax_0: __c_anonymous_eax_0,
         pub eax_1: __c_anonymous_eax_1,
@@ -470,7 +469,6 @@ s_no_extra_traits! {
         pub regs: __c_anonymous_regs,
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_cpu_topology_info_data {
         pub root: cpu_topology_root_info,
         pub package: cpu_topology_package_info,
@@ -481,16 +479,12 @@ s_no_extra_traits! {
         pub id: u32,
         pub type_: topology_level_type,
         pub level: u32,
-        #[cfg(libc_union)]
         pub data: __c_anonymous_cpu_topology_info_data,
-        #[cfg(not(libc_union))]
-        pub data: cpu_topology_core_info,
     }
 }
 
 cfg_if! {
     if #[cfg(feature = "extra_traits")] {
-        #[cfg(libc_union)]
         impl PartialEq for cpuid_info {
             fn eq(&self, other: &cpuid_info) -> bool {
                 unsafe {
@@ -503,9 +497,7 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl Eq for cpuid_info {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for cpuid_info {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 unsafe {
@@ -521,7 +513,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_cpu_topology_info_data {
             fn eq(&self, other: &__c_anonymous_cpu_topology_info_data) -> bool {
                 unsafe {
@@ -531,9 +522,7 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_cpu_topology_info_data {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_cpu_topology_info_data {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 unsafe {
diff --git a/src/unix/hurd/mod.rs b/src/unix/hurd/mod.rs
index ad422fe718349..c02e228604fb8 100644
--- a/src/unix/hurd/mod.rs
+++ b/src/unix/hurd/mod.rs
@@ -4675,15 +4675,8 @@ safe_f! {
     }
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    } else {
-        mod no_align;
-        pub use self::no_align::*;
-    }
-}
+mod align;
+pub use self::align::*;
 
 cfg_if! {
     if #[cfg(target_pointer_width = "64")] {
diff --git a/src/unix/hurd/no_align.rs b/src/unix/hurd/no_align.rs
deleted file mode 100644
index 1dd7d8e541d29..0000000000000
--- a/src/unix/hurd/no_align.rs
+++ /dev/null
@@ -1 +0,0 @@
-// Placeholder file
diff --git a/src/unix/linux_like/android/b32/x86/mod.rs b/src/unix/linux_like/android/b32/x86/mod.rs
index 64ce93dd22916..b29f7dea5c483 100644
--- a/src/unix/linux_like/android/b32/x86/mod.rs
+++ b/src/unix/linux_like/android/b32/x86/mod.rs
@@ -619,9 +619,5 @@ f! {
     }
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
\ No newline at end of file
diff --git a/src/unix/linux_like/android/b64/aarch64/mod.rs b/src/unix/linux_like/android/b64/aarch64/mod.rs
index bd3146deb7f9f..93659c7c0aabe 100644
--- a/src/unix/linux_like/android/b64/aarch64/mod.rs
+++ b/src/unix/linux_like/android/b64/aarch64/mod.rs
@@ -421,16 +421,8 @@ pub const PROT_MTE: ::c_int = 0x20;
 pub const AT_SYSINFO_EHDR: ::c_ulong = 33;
 pub const AT_VECTOR_SIZE_ARCH: ::c_ulong = 2;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
 
-cfg_if! {
-    if #[cfg(libc_int128)] {
-        mod int128;
-        pub use self::int128::*;
-    }
-}
+mod int128;
+pub use self::int128::*;
diff --git a/src/unix/linux_like/android/b64/riscv64/mod.rs b/src/unix/linux_like/android/b64/riscv64/mod.rs
index 209f050f25ce5..9ad629f8b2528 100644
--- a/src/unix/linux_like/android/b64/riscv64/mod.rs
+++ b/src/unix/linux_like/android/b64/riscv64/mod.rs
@@ -357,9 +357,5 @@ pub const AT_L3_CACHESIZE: ::c_ulong = 46;
 pub const AT_L3_CACHEGEOMETRY: ::c_ulong = 47;
 pub const AT_VECTOR_SIZE_ARCH: ::c_ulong = 9;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/android/b64/x86_64/mod.rs b/src/unix/linux_like/android/b64/x86_64/mod.rs
index a7363304c65ce..3550e1f21199b 100644
--- a/src/unix/linux_like/android/b64/x86_64/mod.rs
+++ b/src/unix/linux_like/android/b64/x86_64/mod.rs
@@ -798,9 +798,5 @@ pub const REG_CR2: ::c_int = 22;
 pub const AT_SYSINFO_EHDR: ::c_ulong = 33;
 pub const AT_VECTOR_SIZE_ARCH: ::c_ulong = 3;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/android/mod.rs b/src/unix/linux_like/android/mod.rs
index a8e935967c132..5a719a7501c00 100644
--- a/src/unix/linux_like/android/mod.rs
+++ b/src/unix/linux_like/android/mod.rs
@@ -612,7 +612,6 @@ s_no_extra_traits! {
         __value: [[::c_char; 4]; 23],
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_ifr_ifru {
         pub ifru_addr: ::sockaddr,
         pub ifru_dstaddr: ::sockaddr,
@@ -632,13 +631,9 @@ s_no_extra_traits! {
     pub struct ifreq {
         /// interface name, e.g. "en0"
         pub ifr_name: [::c_char; ::IFNAMSIZ],
-        #[cfg(libc_union)]
         pub ifr_ifru: __c_anonymous_ifr_ifru,
-        #[cfg(not(libc_union))]
-        pub ifr_ifru: ::sockaddr,
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_ifc_ifcu {
         pub ifcu_buf: *mut ::c_char,
         pub ifcu_req: *mut ::ifreq,
@@ -649,10 +644,7 @@ s_no_extra_traits! {
     networks accessible).  */
     pub struct ifconf {
         pub ifc_len: ::c_int,       /* Size of buffer.  */
-        #[cfg(libc_union)]
         pub ifc_ifcu: __c_anonymous_ifc_ifcu,
-        #[cfg(not(libc_union))]
-        pub ifc_ifcu: *mut ::ifreq,
     }
 
 }
@@ -1002,7 +994,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_ifr_ifru {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("ifr_ifru")
@@ -1031,7 +1022,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_ifc_ifcu {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("ifr_ifru")
diff --git a/src/unix/linux_like/emscripten/mod.rs b/src/unix/linux_like/emscripten/mod.rs
index 1dc607496a2ad..6a64a96879684 100644
--- a/src/unix/linux_like/emscripten/mod.rs
+++ b/src/unix/linux_like/emscripten/mod.rs
@@ -1782,13 +1782,7 @@ extern "C" {
 mod lfs64;
 pub use self::lfs64::*;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        #[macro_use]
-        mod align;
-    } else {
-        #[macro_use]
-        mod no_align;
-    }
-}
+#[macro_use]
+mod align;
+
 expand_align!();
diff --git a/src/unix/linux_like/emscripten/no_align.rs b/src/unix/linux_like/emscripten/no_align.rs
deleted file mode 100644
index 768dc73a434f6..0000000000000
--- a/src/unix/linux_like/emscripten/no_align.rs
+++ /dev/null
@@ -1,63 +0,0 @@
-macro_rules! expand_align {
-    () => {
-        s! {
-            pub struct pthread_mutex_t {
-                __align: [::c_long; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_MUTEX_T],
-            }
-
-            pub struct pthread_rwlock_t {
-                __align: [::c_long; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_RWLOCK_T],
-            }
-
-            pub struct pthread_mutexattr_t {
-                __align: [::c_int; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_MUTEXATTR_T],
-            }
-
-            pub struct pthread_rwlockattr_t {
-                __align: [::c_int; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_RWLOCKATTR_T],
-            }
-
-            pub struct pthread_condattr_t {
-                __align: [::c_int; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_CONDATTR_T],
-            }
-        }
-
-        s_no_extra_traits! {
-            pub struct pthread_cond_t {
-                __align: [*const ::c_void; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_COND_T],
-            }
-        }
-
-        cfg_if! {
-            if #[cfg(feature = "extra_traits")] {
-                impl PartialEq for pthread_cond_t {
-                    fn eq(&self, other: &pthread_cond_t) -> bool {
-                        self.size
-                            .iter()
-                            .zip(other.size.iter())
-                            .all(|(a,b)| a == b)
-                    }
-                }
-                impl Eq for pthread_cond_t {}
-                impl ::fmt::Debug for pthread_cond_t {
-                    fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
-                        f.debug_struct("pthread_cond_t")
-                            // FIXME: .field("size", &self.size)
-                            .finish()
-                    }
-                }
-                impl ::hash::Hash for pthread_cond_t {
-                    fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
-                        self.size.hash(state);
-                    }
-                }
-            }
-        }
-    };
-}
diff --git a/src/unix/linux_like/linux/gnu/b32/arm/mod.rs b/src/unix/linux_like/linux/gnu/b32/arm/mod.rs
index 4a14d692c8652..ed88a802636db 100644
--- a/src/unix/linux_like/linux/gnu/b32/arm/mod.rs
+++ b/src/unix/linux_like/linux/gnu/b32/arm/mod.rs
@@ -857,9 +857,5 @@ pub const SYS_futex_waitv: ::c_long = 449;
 pub const SYS_set_mempolicy_home_node: ::c_long = 450;
 pub const SYS_mseal: ::c_long = 462;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
\ No newline at end of file
diff --git a/src/unix/linux_like/linux/gnu/b32/csky/mod.rs b/src/unix/linux_like/linux/gnu/b32/csky/mod.rs
index 5e92e30073bee..16b2f9b84034e 100644
--- a/src/unix/linux_like/linux/gnu/b32/csky/mod.rs
+++ b/src/unix/linux_like/linux/gnu/b32/csky/mod.rs
@@ -733,9 +733,5 @@ pub const SYS_process_mrelease: ::c_long = 448;
 pub const SYS_futex_waitv: ::c_long = 449;
 pub const SYS_set_mempolicy_home_node: ::c_long = 450;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/gnu/b32/mips/mod.rs b/src/unix/linux_like/linux/gnu/b32/mips/mod.rs
index fa2707500dbe4..8f5ed0f348459 100644
--- a/src/unix/linux_like/linux/gnu/b32/mips/mod.rs
+++ b/src/unix/linux_like/linux/gnu/b32/mips/mod.rs
@@ -811,9 +811,5 @@ pub const B4000000: ::speed_t = 0o010017;
 
 pub const EHWPOISON: ::c_int = 168;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/gnu/b32/riscv32/mod.rs b/src/unix/linux_like/linux/gnu/b32/riscv32/mod.rs
index 65b7aaa783559..8a75e6d42b32b 100644
--- a/src/unix/linux_like/linux/gnu/b32/riscv32/mod.rs
+++ b/src/unix/linux_like/linux/gnu/b32/riscv32/mod.rs
@@ -805,9 +805,5 @@ pub const SYS_process_mrelease: ::c_long = 448;
 pub const SYS_futex_waitv: ::c_long = 449;
 pub const SYS_set_mempolicy_home_node: ::c_long = 450;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/gnu/b32/sparc/mod.rs b/src/unix/linux_like/linux/gnu/b32/sparc/mod.rs
index da9cf29c48668..16b836f7e6128 100644
--- a/src/unix/linux_like/linux/gnu/b32/sparc/mod.rs
+++ b/src/unix/linux_like/linux/gnu/b32/sparc/mod.rs
@@ -849,9 +849,5 @@ pub const SYS_process_mrelease: ::c_long = 448;
 pub const SYS_futex_waitv: ::c_long = 449;
 pub const SYS_set_mempolicy_home_node: ::c_long = 450;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/gnu/b32/x86/mod.rs b/src/unix/linux_like/linux/gnu/b32/x86/mod.rs
index 4391eb3fa7968..73e7a394775d6 100644
--- a/src/unix/linux_like/linux/gnu/b32/x86/mod.rs
+++ b/src/unix/linux_like/linux/gnu/b32/x86/mod.rs
@@ -1094,9 +1094,5 @@ extern "C" {
     pub fn swapcontext(uocp: *mut ucontext_t, ucp: *const ucontext_t) -> ::c_int;
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/gnu/b64/aarch64/fallback.rs b/src/unix/linux_like/linux/gnu/b64/aarch64/fallback.rs
deleted file mode 100644
index 398fbb53755c8..0000000000000
--- a/src/unix/linux_like/linux/gnu/b64/aarch64/fallback.rs
+++ /dev/null
@@ -1,8 +0,0 @@
-s! {
-    #[repr(align(16))]
-    pub struct user_fpsimd_struct {
-        pub vregs: [[u64; 2]; 32],
-        pub fpsr: ::c_uint,
-        pub fpcr: ::c_uint,
-    }
-}
diff --git a/src/unix/linux_like/linux/gnu/b64/aarch64/mod.rs b/src/unix/linux_like/linux/gnu/b64/aarch64/mod.rs
index c8a805cdd36cb..821843a84fb79 100644
--- a/src/unix/linux_like/linux/gnu/b64/aarch64/mod.rs
+++ b/src/unix/linux_like/linux/gnu/b64/aarch64/mod.rs
@@ -918,21 +918,8 @@ cfg_if! {
     }
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-
-
-}
+mod align;
+pub use self::align::*;
 
-cfg_if! {
-    if #[cfg(libc_int128)] {
-        mod int128;
-        pub use self::int128::*;
-    } else if #[cfg(libc_align)] {
-        mod fallback;
-        pub use self::fallback::*;
-    }
-}
+mod int128;
+pub use self::int128::*;
\ No newline at end of file
diff --git a/src/unix/linux_like/linux/gnu/b64/loongarch64/mod.rs b/src/unix/linux_like/linux/gnu/b64/loongarch64/mod.rs
index ac3f88905f38e..a3c1706aa62c0 100644
--- a/src/unix/linux_like/linux/gnu/b64/loongarch64/mod.rs
+++ b/src/unix/linux_like/linux/gnu/b64/loongarch64/mod.rs
@@ -892,9 +892,5 @@ pub const EPOLL_CLOEXEC: ::c_int = 0x80000;
 pub const EFD_CLOEXEC: ::c_int = 0x80000;
 pub const EFD_NONBLOCK: ::c_int = 0x800;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/gnu/b64/mips64/mod.rs b/src/unix/linux_like/linux/gnu/b64/mips64/mod.rs
index f7b52be805cab..192881ab41a31 100644
--- a/src/unix/linux_like/linux/gnu/b64/mips64/mod.rs
+++ b/src/unix/linux_like/linux/gnu/b64/mips64/mod.rs
@@ -926,9 +926,5 @@ extern "C" {
     ) -> ::c_int;
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/gnu/b64/powerpc64/mod.rs b/src/unix/linux_like/linux/gnu/b64/powerpc64/mod.rs
index 3088c25a2646f..0f811c689316b 100644
--- a/src/unix/linux_like/linux/gnu/b64/powerpc64/mod.rs
+++ b/src/unix/linux_like/linux/gnu/b64/powerpc64/mod.rs
@@ -971,9 +971,5 @@ extern "C" {
     ) -> ::c_int;
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/gnu/b64/riscv64/mod.rs b/src/unix/linux_like/linux/gnu/b64/riscv64/mod.rs
index 64f5cf10f8583..750ee8f8436e8 100644
--- a/src/unix/linux_like/linux/gnu/b64/riscv64/mod.rs
+++ b/src/unix/linux_like/linux/gnu/b64/riscv64/mod.rs
@@ -852,9 +852,5 @@ pub const SYS_process_mrelease: ::c_long = 448;
 pub const SYS_futex_waitv: ::c_long = 449;
 pub const SYS_set_mempolicy_home_node: ::c_long = 450;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/gnu/b64/sparc64/mod.rs b/src/unix/linux_like/linux/gnu/b64/sparc64/mod.rs
index de2f0d6e470f6..5b447bbdad474 100644
--- a/src/unix/linux_like/linux/gnu/b64/sparc64/mod.rs
+++ b/src/unix/linux_like/linux/gnu/b64/sparc64/mod.rs
@@ -923,9 +923,5 @@ extern "C" {
     ) -> ::c_int;
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs b/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs
index 609c74429c5bc..86536f185750f 100644
--- a/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs
+++ b/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs
@@ -816,9 +816,5 @@ cfg_if! {
     }
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/gnu/mod.rs b/src/unix/linux_like/linux/gnu/mod.rs
index 75d150c90d58a..78669ff795c6b 100644
--- a/src/unix/linux_like/linux/gnu/mod.rs
+++ b/src/unix/linux_like/linux/gnu/mod.rs
@@ -353,7 +353,6 @@ s! {
         pub arch: ::__u32,
         pub instruction_pointer: ::__u64,
         pub stack_pointer: ::__u64,
-        #[cfg(libc_union)]
         pub u: __c_anonymous_ptrace_syscall_info_data,
     }
 
@@ -656,7 +655,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_ptrace_syscall_info_data {
             fn eq(&self, other: &__c_anonymous_ptrace_syscall_info_data) -> bool {
                 unsafe {
@@ -667,10 +665,8 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_ptrace_syscall_info_data {}
 
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_ptrace_syscall_info_data {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 unsafe {
@@ -683,7 +679,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::hash::Hash for __c_anonymous_ptrace_syscall_info_data {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
@@ -1580,12 +1575,5 @@ cfg_if! {
     }
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    } else {
-        mod no_align;
-        pub use self::no_align::*;
-    }
-}
+mod align;
+pub use self::align::*;
\ No newline at end of file
diff --git a/src/unix/linux_like/linux/gnu/no_align.rs b/src/unix/linux_like/linux/gnu/no_align.rs
deleted file mode 100644
index e32bf673d140e..0000000000000
--- a/src/unix/linux_like/linux/gnu/no_align.rs
+++ /dev/null
@@ -1,10 +0,0 @@
-s! {
-    // FIXME this is actually a union
-    pub struct sem_t {
-        #[cfg(target_pointer_width = "32")]
-        __size: [::c_char; 16],
-        #[cfg(target_pointer_width = "64")]
-        __size: [::c_char; 32],
-        __align: [::c_long; 0],
-    }
-}
diff --git a/src/unix/linux_like/linux/mod.rs b/src/unix/linux_like/linux/mod.rs
index 1973b3f574efa..1b894d250e149 100644
--- a/src/unix/linux_like/linux/mod.rs
+++ b/src/unix/linux_like/linux/mod.rs
@@ -823,7 +823,6 @@ s_no_extra_traits! {
         pad: [::c_long; 4],
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_ifr_ifru {
         pub ifru_addr: ::sockaddr,
         pub ifru_dstaddr: ::sockaddr,
@@ -843,13 +842,9 @@ s_no_extra_traits! {
     pub struct ifreq {
         /// interface name, e.g. "en0"
         pub ifr_name: [::c_char; ::IFNAMSIZ],
-        #[cfg(libc_union)]
         pub ifr_ifru: __c_anonymous_ifr_ifru,
-        #[cfg(not(libc_union))]
-        pub ifr_ifru: ::sockaddr,
     }
 
-    #[cfg(libc_union)]
     pub union __c_anonymous_ifc_ifcu {
         pub ifcu_buf: *mut ::c_char,
         pub ifcu_req: *mut ::ifreq,
@@ -860,10 +855,7 @@ s_no_extra_traits! {
     networks accessible).  */
     pub struct ifconf {
         pub ifc_len: ::c_int,       /* Size of buffer.  */
-        #[cfg(libc_union)]
         pub ifc_ifcu: __c_anonymous_ifc_ifcu,
-        #[cfg(not(libc_union))]
-        pub ifc_ifcu: *mut ::ifreq,
     }
 
     pub struct hwtstamp_config {
@@ -1285,7 +1277,6 @@ cfg_if! {
                 self.mq_curmsgs.hash(state);
             }
         }
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_ifr_ifru {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("ifr_ifru")
@@ -1314,7 +1305,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_ifc_ifcu {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 f.debug_struct("ifr_ifru")
@@ -4310,19 +4300,15 @@ pub const CANXL_MAX_DLEN: usize = 2048;
 pub const CANXL_XLF: ::c_int = 0x80;
 pub const CANXL_SEC: ::c_int = 0x01;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        pub const CAN_MTU: usize = ::mem::size_of::<can_frame>();
-        pub const CANFD_MTU: usize = ::mem::size_of::<canfd_frame>();
-        pub const CANXL_MTU: usize = ::mem::size_of::<canxl_frame>();
-        // FIXME: use `core::mem::offset_of!` once that is available
-        // https://github.com/rust-lang/rfcs/pull/3308
-        // pub const CANXL_HDR_SIZE: usize = core::mem::offset_of!(canxl_frame, data);
-        pub const CANXL_HDR_SIZE: usize = 12;
-        pub const CANXL_MIN_MTU: usize = CANXL_HDR_SIZE + 64;
-        pub const CANXL_MAX_MTU: usize = CANXL_MTU;
-    }
-}
+pub const CAN_MTU: usize = ::mem::size_of::<can_frame>();
+pub const CANFD_MTU: usize = ::mem::size_of::<canfd_frame>();
+pub const CANXL_MTU: usize = ::mem::size_of::<canxl_frame>();
+// FIXME: use `core::mem::offset_of!` once that is available
+// https://github.com/rust-lang/rfcs/pull/3308
+// pub const CANXL_HDR_SIZE: usize = core::mem::offset_of!(canxl_frame, data);
+pub const CANXL_HDR_SIZE: usize = 12;
+pub const CANXL_MIN_MTU: usize = CANXL_HDR_SIZE + 64;
+pub const CANXL_MAX_MTU: usize = CANXL_MTU;
 
 pub const CAN_RAW: ::c_int = 1;
 pub const CAN_BCM: ::c_int = 2;
@@ -5689,15 +5675,8 @@ cfg_if! {
 mod arch;
 pub use self::arch::*;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        #[macro_use]
-        mod align;
-    } else {
-        #[macro_use]
-        mod no_align;
-    }
-}
+#[macro_use]
+mod align;
 expand_align!();
 
 cfg_if! {
diff --git a/src/unix/linux_like/linux/musl/b32/arm/mod.rs b/src/unix/linux_like/linux/musl/b32/arm/mod.rs
index 4ac3e60d43079..58097f1434015 100644
--- a/src/unix/linux_like/linux/musl/b32/arm/mod.rs
+++ b/src/unix/linux_like/linux/musl/b32/arm/mod.rs
@@ -846,9 +846,5 @@ extern "C" {
     pub fn getrandom(buf: *mut ::c_void, buflen: ::size_t, flags: ::c_uint) -> ::ssize_t;
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/musl/b32/mips/mod.rs b/src/unix/linux_like/linux/musl/b32/mips/mod.rs
index 2fb405bbc6ceb..ab7a55b754c5e 100644
--- a/src/unix/linux_like/linux/musl/b32/mips/mod.rs
+++ b/src/unix/linux_like/linux/musl/b32/mips/mod.rs
@@ -780,9 +780,5 @@ pub const SYS_process_mrelease: ::c_long = 4000 + 448;
 pub const SYS_futex_waitv: ::c_long = 4000 + 449;
 pub const SYS_set_mempolicy_home_node: ::c_long = 4000 + 450;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/musl/b32/riscv32/mod.rs b/src/unix/linux_like/linux/musl/b32/riscv32/mod.rs
index f963f645a9f10..8568f2f338094 100644
--- a/src/unix/linux_like/linux/musl/b32/riscv32/mod.rs
+++ b/src/unix/linux_like/linux/musl/b32/riscv32/mod.rs
@@ -790,9 +790,5 @@ pub const SYS_process_madvise: ::c_long = 440;
 pub const SYS_epoll_pwait2: ::c_long = 441;
 pub const SYS_mount_setattr: ::c_long = 442;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/musl/b32/x86/mod.rs b/src/unix/linux_like/linux/musl/b32/x86/mod.rs
index 7fad04677f8a4..f43c7ea60f8c7 100644
--- a/src/unix/linux_like/linux/musl/b32/x86/mod.rs
+++ b/src/unix/linux_like/linux/musl/b32/x86/mod.rs
@@ -961,9 +961,5 @@ extern "C" {
     pub fn getrandom(buf: *mut ::c_void, buflen: ::size_t, flags: ::c_uint) -> ::ssize_t;
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/musl/b64/aarch64/mod.rs b/src/unix/linux_like/linux/musl/b64/aarch64/mod.rs
index 24e6b8419253a..1d84a15790cbc 100644
--- a/src/unix/linux_like/linux/musl/b64/aarch64/mod.rs
+++ b/src/unix/linux_like/linux/musl/b64/aarch64/mod.rs
@@ -644,16 +644,8 @@ pub const IEXTEN: ::tcflag_t = 0x00008000;
 pub const TOSTOP: ::tcflag_t = 0x00000100;
 pub const FLUSHO: ::tcflag_t = 0x00001000;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
 
-cfg_if! {
-    if #[cfg(libc_int128)] {
-        mod int128;
-        pub use self::int128::*;
-    }
-}
+mod int128;
+pub use self::int128::*;
diff --git a/src/unix/linux_like/linux/musl/b64/loongarch64/mod.rs b/src/unix/linux_like/linux/musl/b64/loongarch64/mod.rs
index 59a824b237306..ed47b50b2b495 100644
--- a/src/unix/linux_like/linux/musl/b64/loongarch64/mod.rs
+++ b/src/unix/linux_like/linux/musl/b64/loongarch64/mod.rs
@@ -661,9 +661,5 @@ pub const IEXTEN: ::tcflag_t = 0x00008000;
 pub const TOSTOP: ::tcflag_t = 0x00000100;
 pub const FLUSHO: ::tcflag_t = 0x00001000;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/musl/b64/riscv64/mod.rs b/src/unix/linux_like/linux/musl/b64/riscv64/mod.rs
index 393f54d3ff773..2a37bd976bc7c 100644
--- a/src/unix/linux_like/linux/musl/b64/riscv64/mod.rs
+++ b/src/unix/linux_like/linux/musl/b64/riscv64/mod.rs
@@ -719,9 +719,5 @@ pub const REG_A0: usize = 10;
 pub const REG_S2: usize = 18;
 pub const REG_NARGS: usize = 8;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/musl/b64/x86_64/mod.rs b/src/unix/linux_like/linux/musl/b64/x86_64/mod.rs
index dc617d42fe0cc..b1ede42064f97 100644
--- a/src/unix/linux_like/linux/musl/b64/x86_64/mod.rs
+++ b/src/unix/linux_like/linux/musl/b64/x86_64/mod.rs
@@ -909,9 +909,5 @@ pub const IEXTEN: ::tcflag_t = 0x00008000;
 pub const TOSTOP: ::tcflag_t = 0x00000100;
 pub const FLUSHO: ::tcflag_t = 0x00001000;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/no_align.rs b/src/unix/linux_like/linux/no_align.rs
deleted file mode 100644
index 328a5cc484231..0000000000000
--- a/src/unix/linux_like/linux/no_align.rs
+++ /dev/null
@@ -1,144 +0,0 @@
-macro_rules! expand_align {
-    () => {
-        s! {
-            pub struct pthread_mutexattr_t {
-                #[cfg(any(target_arch = "x86_64",
-                          target_arch = "powerpc64",
-                          target_arch = "mips64",
-                          target_arch = "mips64r6",
-                          target_arch = "s390x",
-                          target_arch = "sparc64",
-                          target_arch = "riscv64",
-                          target_arch = "riscv32",
-                          target_arch = "loongarch64",
-                          all(target_arch = "aarch64",
-                              any(target_env = "musl", target_env = "ohos"))))]
-                __align: [::c_int; 0],
-                #[cfg(not(any(target_arch = "x86_64",
-                              target_arch = "powerpc64",
-                              target_arch = "mips64",
-                              target_arch = "mips64r6",
-                              target_arch = "s390x",
-                              target_arch = "sparc64",
-                              target_arch = "riscv64",
-                              target_arch = "riscv32",
-                              target_arch = "loongarch64",
-                              all(target_arch = "aarch64",
-                                  any(target_env = "musl", target_env = "ohos")))))]
-                __align: [::c_long; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_MUTEXATTR_T],
-            }
-
-            pub struct pthread_rwlockattr_t {
-                #[cfg(any(target_env = "musl", target_env = "ohos"))]
-                __align: [::c_int; 0],
-                #[cfg(not(any(target_env = "musl", target_env = "ohos")))]
-                __align: [::c_long; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_RWLOCKATTR_T],
-            }
-
-            pub struct pthread_condattr_t {
-                __align: [::c_int; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_CONDATTR_T],
-            }
-
-            pub struct pthread_barrierattr_t {
-                __align: [::c_int; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_BARRIERATTR_T],
-            }
-
-            pub struct fanotify_event_metadata {
-                __align: [::c_long; 0],
-                pub event_len: __u32,
-                pub vers: __u8,
-                pub reserved: __u8,
-                pub metadata_len: __u16,
-                pub mask: __u64,
-                pub fd: ::c_int,
-                pub pid: ::c_int,
-            }
-        }
-
-        s_no_extra_traits! {
-            pub struct pthread_cond_t {
-                #[cfg(any(target_env = "musl", target_env = "ohos"))]
-                __align: [*const ::c_void; 0],
-                #[cfg(not(any(target_env = "musl", target_env = "ohos")))]
-                __align: [::c_longlong; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_COND_T],
-            }
-
-            pub struct pthread_mutex_t {
-                #[cfg(any(target_arch = "mips",
-                          target_arch = "mips32r6",
-                          target_arch = "arm",
-                          target_arch = "m68k",
-                          target_arch = "csky",
-                          target_arch = "powerpc",
-                          target_arch = "sparc",
-                          all(target_arch = "x86_64",
-                              target_pointer_width = "32")))]
-                __align: [::c_long; 0],
-                #[cfg(not(any(target_arch = "mips",
-                              target_arch = "mips32r6",
-                              target_arch = "arm",
-                              target_arch = "m68k",
-                              target_arch = "csky",
-                              target_arch = "powerpc",
-                              target_arch = "sparc",
-                              all(target_arch = "x86_64",
-                                  target_pointer_width = "32"))))]
-                __align: [::c_longlong; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_MUTEX_T],
-            }
-
-            pub struct pthread_rwlock_t {
-                #[cfg(any(target_arch = "mips",
-                          target_arch = "mips32r6",
-                          target_arch = "arm",
-                          target_arch = "m68k",
-                          target_arch = "csky",
-                          target_arch = "powerpc",
-                          target_arch = "sparc",
-                          all(target_arch = "x86_64",
-                              target_pointer_width = "32")))]
-                __align: [::c_long; 0],
-                #[cfg(not(any(target_arch = "mips",
-                              target_arch = "mips32r6",
-                              target_arch = "arm",
-                              target_arch = "m68k",
-                              target_arch = "csky",
-                              target_arch = "powerpc",
-                              target_arch = "sparc",
-                              all(target_arch = "x86_64",
-                                  target_pointer_width = "32"))))]
-                __align: [::c_longlong; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_RWLOCK_T],
-            }
-
-            pub struct pthread_barrier_t {
-                #[cfg(any(target_arch = "mips",
-                          target_arch = "mips32r6",
-                          target_arch = "arm",
-                          target_arch = "m68k",
-                          target_arch = "csky",
-                          target_arch = "powerpc",
-                          target_arch = "sparc",
-                          all(target_arch = "x86_64",
-                              target_pointer_width = "32")))]
-                __align: [::c_long; 0],
-                #[cfg(not(any(target_arch = "mips",
-                              target_arch = "mips32r6",
-                              target_arch = "arm",
-                              target_arch = "m68k",
-                              target_arch = "csky",
-                              target_arch = "powerpc",
-                              target_arch = "sparc",
-                              all(target_arch = "x86_64",
-                                  target_pointer_width = "32"))))]
-                __align: [::c_longlong; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_BARRIER_T],
-            }
-        }
-    };
-}
diff --git a/src/unix/linux_like/linux/uclibc/arm/mod.rs b/src/unix/linux_like/linux/uclibc/arm/mod.rs
index cff82f005acee..69187670587d6 100644
--- a/src/unix/linux_like/linux/uclibc/arm/mod.rs
+++ b/src/unix/linux_like/linux/uclibc/arm/mod.rs
@@ -914,12 +914,5 @@ pub const SYS_process_mrelease: ::c_long = 448;
 pub const SYS_futex_waitv: ::c_long = 449;
 pub const SYS_set_mempolicy_home_node: ::c_long = 450;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    } else {
-        mod no_align;
-        pub use self::no_align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/uclibc/arm/no_align.rs b/src/unix/linux_like/linux/uclibc/arm/no_align.rs
deleted file mode 100644
index e32bf673d140e..0000000000000
--- a/src/unix/linux_like/linux/uclibc/arm/no_align.rs
+++ /dev/null
@@ -1,10 +0,0 @@
-s! {
-    // FIXME this is actually a union
-    pub struct sem_t {
-        #[cfg(target_pointer_width = "32")]
-        __size: [::c_char; 16],
-        #[cfg(target_pointer_width = "64")]
-        __size: [::c_char; 32],
-        __align: [::c_long; 0],
-    }
-}
diff --git a/src/unix/linux_like/linux/uclibc/mips/mips32/mod.rs b/src/unix/linux_like/linux/uclibc/mips/mips32/mod.rs
index a5aca85a3a741..9e5765e9568f1 100644
--- a/src/unix/linux_like/linux/uclibc/mips/mips32/mod.rs
+++ b/src/unix/linux_like/linux/uclibc/mips/mips32/mod.rs
@@ -681,12 +681,5 @@ extern "C" {
     ) -> ::c_int;
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    } else {
-        mod no_align;
-        pub use self::no_align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/uclibc/mips/mips32/no_align.rs b/src/unix/linux_like/linux/uclibc/mips/mips32/no_align.rs
deleted file mode 100644
index e32bf673d140e..0000000000000
--- a/src/unix/linux_like/linux/uclibc/mips/mips32/no_align.rs
+++ /dev/null
@@ -1,10 +0,0 @@
-s! {
-    // FIXME this is actually a union
-    pub struct sem_t {
-        #[cfg(target_pointer_width = "32")]
-        __size: [::c_char; 16],
-        #[cfg(target_pointer_width = "64")]
-        __size: [::c_char; 32],
-        __align: [::c_long; 0],
-    }
-}
diff --git a/src/unix/linux_like/linux/uclibc/mips/mips64/mod.rs b/src/unix/linux_like/linux/uclibc/mips/mips64/mod.rs
index 8ca100fcd268f..4ac13f5c77866 100644
--- a/src/unix/linux_like/linux/uclibc/mips/mips64/mod.rs
+++ b/src/unix/linux_like/linux/uclibc/mips/mips64/mod.rs
@@ -196,12 +196,5 @@ pub const __SIZEOF_PTHREAD_BARRIER_T: usize = 32;
 
 pub const SYS_gettid: ::c_long = 5178; // Valid for n64
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    } else {
-        mod no_align;
-        pub use self::no_align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/linux_like/linux/uclibc/mips/mips64/no_align.rs b/src/unix/linux_like/linux/uclibc/mips/mips64/no_align.rs
deleted file mode 100644
index 8909114cdfa42..0000000000000
--- a/src/unix/linux_like/linux/uclibc/mips/mips64/no_align.rs
+++ /dev/null
@@ -1,7 +0,0 @@
-s! {
-    // FIXME this is actually a union
-    pub struct sem_t {
-        __size: [::c_char; 32],
-        __align: [::c_long; 0],
-    }
-}
diff --git a/src/unix/linux_like/linux/uclibc/no_align.rs b/src/unix/linux_like/linux/uclibc/no_align.rs
deleted file mode 100644
index a73dbded57ac7..0000000000000
--- a/src/unix/linux_like/linux/uclibc/no_align.rs
+++ /dev/null
@@ -1,53 +0,0 @@
-macro_rules! expand_align {
-    () => {
-        s! {
-            pub struct pthread_mutex_t {
-                #[cfg(any(target_arch = "mips",
-                          target_arch = "arm",
-                          target_arch = "powerpc"))]
-                __align: [::c_long; 0],
-                #[cfg(any(libc_align,
-                          target_arch = "mips",
-                          target_arch = "arm",
-                          target_arch = "powerpc"))]
-                __align: [::c_longlong; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_MUTEX_T],
-            }
-
-            pub struct pthread_rwlock_t {
-                #[cfg(any(target_arch = "mips",
-                          target_arch = "arm",
-                          target_arch = "powerpc"))]
-                __align: [::c_long; 0],
-                #[cfg(not(any(
-                    target_arch = "mips",
-                    target_arch = "arm",
-                    target_arch = "powerpc")))]
-                __align: [::c_longlong; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_RWLOCK_T],
-            }
-
-            pub struct pthread_mutexattr_t {
-                #[cfg(any(target_arch = "x86_64", target_arch = "powerpc64",
-                          target_arch = "mips64", target_arch = "s390x",
-                          target_arch = "sparc64"))]
-                __align: [::c_int; 0],
-                #[cfg(not(any(target_arch = "x86_64", target_arch = "powerpc64",
-                              target_arch = "mips64", target_arch = "s390x",
-                              target_arch = "sparc64")))]
-                __align: [::c_long; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_MUTEXATTR_T],
-            }
-
-            pub struct pthread_cond_t {
-                __align: [::c_longlong; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_COND_T],
-            }
-
-            pub struct pthread_condattr_t {
-                __align: [::c_int; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_CONDATTR_T],
-            }
-        }
-    }
-}
diff --git a/src/unix/mod.rs b/src/unix/mod.rs
index 6bab825b0449b..2a492fad9a4f2 100644
--- a/src/unix/mod.rs
+++ b/src/unix/mod.rs
@@ -1622,32 +1622,7 @@ cfg_if! {
     }
 }
 
-cfg_if! {
-    if #[cfg(libc_core_cvoid)] {
-        pub use ::ffi::c_void;
-    } else {
-        // Use repr(u8) as LLVM expects `void*` to be the same as `i8*` to help
-        // enable more optimization opportunities around it recognizing things
-        // like malloc/free.
-        #[repr(u8)]
-        #[allow(missing_copy_implementations)]
-        #[allow(missing_debug_implementations)]
-        pub enum c_void {
-            // Two dummy variants so the #[repr] attribute can be used.
-            #[doc(hidden)]
-            __variant1,
-            #[doc(hidden)]
-            __variant2,
-        }
-    }
-}
+pub use ::ffi::c_void;
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    } else {
-        mod no_align;
-        pub use self::no_align::*;
-    }
-}
+mod align;
+pub use self::align::*;
diff --git a/src/unix/newlib/mod.rs b/src/unix/newlib/mod.rs
index 29693f6ec2402..ce45065b039cf 100644
--- a/src/unix/newlib/mod.rs
+++ b/src/unix/newlib/mod.rs
@@ -792,13 +792,6 @@ cfg_if! {
     }
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        #[macro_use]
-        mod align;
-    } else {
-        #[macro_use]
-        mod no_align;
-    }
-}
+#[macro_use]
+mod align;
 expand_align!();
diff --git a/src/unix/newlib/no_align.rs b/src/unix/newlib/no_align.rs
deleted file mode 100644
index ce3aca4ed5723..0000000000000
--- a/src/unix/newlib/no_align.rs
+++ /dev/null
@@ -1,51 +0,0 @@
-macro_rules! expand_align {
-    () => {
-        s! {
-            pub struct pthread_mutex_t { // Unverified
-                #[cfg(any(target_arch = "mips",
-                          target_arch = "arm",
-                          target_arch = "powerpc"))]
-                __align: [::c_long; 0],
-                #[cfg(not(any(target_arch = "mips",
-                              target_arch = "arm",
-                              target_arch = "powerpc")))]
-                __align: [::c_longlong; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_MUTEX_T],
-            }
-
-            pub struct pthread_rwlock_t { // Unverified
-                #[cfg(any(target_arch = "mips",
-                          target_arch = "arm",
-                          target_arch = "powerpc"))]
-                __align: [::c_long; 0],
-                #[cfg(not(any(target_arch = "mips",
-                              target_arch = "arm",
-                              target_arch = "powerpc")))]
-                __align: [::c_longlong; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_RWLOCK_T],
-            }
-
-            pub struct pthread_mutexattr_t { // Unverified
-                #[cfg(any(target_arch = "x86_64", target_arch = "powerpc64",
-                          target_arch = "mips64", target_arch = "s390x",
-                          target_arch = "sparc64"))]
-                __align: [::c_int; 0],
-                #[cfg(not(any(target_arch = "x86_64", target_arch = "powerpc64",
-                              target_arch = "mips64", target_arch = "s390x",
-                              target_arch = "sparc64")))]
-                __align: [::c_long; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_MUTEXATTR_T],
-            }
-
-            pub struct pthread_cond_t { // Unverified
-                __align: [::c_longlong; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_COND_T],
-            }
-
-            pub struct pthread_condattr_t { // Unverified
-                __align: [::c_int; 0],
-                size: [u8; ::__SIZEOF_PTHREAD_CONDATTR_T],
-            }
-        }
-    };
-}
diff --git a/src/unix/no_align.rs b/src/unix/no_align.rs
deleted file mode 100644
index b435d72aa7db0..0000000000000
--- a/src/unix/no_align.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-s! {
-    pub struct in6_addr {
-        pub s6_addr: [u8; 16],
-        __align: [u32; 0],
-    }
-}
-
-pub const IN6ADDR_LOOPBACK_INIT: in6_addr = in6_addr {
-    s6_addr: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
-    __align: [0u32; 0],
-};
-
-pub const IN6ADDR_ANY_INIT: in6_addr = in6_addr {
-    s6_addr: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
-    __align: [0u32; 0],
-};
diff --git a/src/unix/nto/x86_64.rs b/src/unix/nto/x86_64.rs
index 3a1d230bb98eb..29739ac83a3e9 100644
--- a/src/unix/nto/x86_64.rs
+++ b/src/unix/nto/x86_64.rs
@@ -34,10 +34,7 @@ s! {
     #[repr(align(8))]
     pub struct mcontext_t {
         pub cpu: x86_64_cpu_registers,
-        #[cfg(libc_union)]
         pub fpu: x86_64_fpu_registers,
-        #[cfg(not(libc_union))]
-        __reserved: [u8; 1024],
     }
 
     pub struct stack_t {
@@ -80,7 +77,6 @@ s! {
 }
 
 s_no_extra_traits! {
-    #[cfg(libc_union)]
     pub union x86_64_fpu_registers {
         pub fsave_area: fsave_area_64,
         pub fxsave_area: fxsave_area_64,
@@ -91,10 +87,8 @@ s_no_extra_traits! {
 
 cfg_if! {
     if #[cfg(feature = "extra_traits")] {
-        #[cfg(libc_union)]
         impl Eq for x86_64_fpu_registers {}
 
-        #[cfg(libc_union)]
         impl PartialEq for x86_64_fpu_registers {
             fn eq(&self, other: &x86_64_fpu_registers) -> bool {
                 unsafe {
@@ -105,7 +99,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::fmt::Debug for x86_64_fpu_registers {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 unsafe {
@@ -118,7 +111,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl ::hash::Hash for x86_64_fpu_registers {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
diff --git a/src/unix/solarish/mod.rs b/src/unix/solarish/mod.rs
index 63056bfbd7c7c..6c204b383b39a 100644
--- a/src/unix/solarish/mod.rs
+++ b/src/unix/solarish/mod.rs
@@ -541,7 +541,7 @@ s_no_extra_traits! {
         __ss_pad2: [u8; 240],
     }
 
-    #[cfg_attr(all(target_pointer_width = "64", libc_align), repr(align(8)))]
+    #[cfg_attr(target_pointer_width = "64", repr(align(8)))]
     pub struct siginfo_t {
         pub si_signo: ::c_int,
         pub si_code: ::c_int,
@@ -571,15 +571,13 @@ s_no_extra_traits! {
         __sigev_pad2: ::c_int,
     }
 
-    #[cfg(libc_union)]
-    #[cfg_attr(libc_align, repr(align(16)))]
+    #[repr(align(16))]
     pub union pad128_t {
         // pub _q in this structure would be a "long double", of 16 bytes
         pub _l: [i32; 4],
     }
 
-    #[cfg(libc_union)]
-    #[cfg_attr(libc_align, repr(align(16)))]
+    #[repr(align(16))]
     pub union upad128_t {
         // pub _q in this structure would be a "long double", of 16 bytes
         pub _l: [u32; 4],
@@ -947,7 +945,6 @@ cfg_if! {
             }
         }
 
-        #[cfg(libc_union)]
         impl PartialEq for pad128_t {
             fn eq(&self, other: &pad128_t) -> bool {
                 unsafe {
@@ -956,9 +953,7 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl Eq for pad128_t {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for pad128_t {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 unsafe {
@@ -969,7 +964,6 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl ::hash::Hash for pad128_t {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
@@ -978,7 +972,6 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl PartialEq for upad128_t {
             fn eq(&self, other: &upad128_t) -> bool {
                 unsafe {
@@ -987,9 +980,7 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl Eq for upad128_t {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for upad128_t {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 unsafe {
@@ -1000,7 +991,6 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl ::hash::Hash for upad128_t {
             fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
                 unsafe {
diff --git a/src/unix/solarish/x86_64.rs b/src/unix/solarish/x86_64.rs
index bca552f378202..d0e80b5588c46 100644
--- a/src/unix/solarish/x86_64.rs
+++ b/src/unix/solarish/x86_64.rs
@@ -50,7 +50,6 @@ s! {
 }
 
 s_no_extra_traits! {
-    #[cfg(libc_union)]
     pub union __c_anonymous_fp_reg_set {
         pub fpchip_state: __c_anonymous_fpchip_state,
         pub f_fpregs: [[u32; 13]; 10],
@@ -77,7 +76,6 @@ s_no_extra_traits! {
 
 cfg_if! {
     if #[cfg(feature = "extra_traits")] {
-        #[cfg(libc_union)]
         impl PartialEq for __c_anonymous_fp_reg_set {
             fn eq(&self, other: &__c_anonymous_fp_reg_set) -> bool {
                 unsafe {
@@ -90,9 +88,7 @@ cfg_if! {
                 }
             }
         }
-        #[cfg(libc_union)]
         impl Eq for __c_anonymous_fp_reg_set {}
-        #[cfg(libc_union)]
         impl ::fmt::Debug for __c_anonymous_fp_reg_set {
             fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
                 unsafe {
diff --git a/src/vxworks/mod.rs b/src/vxworks/mod.rs
index 314283410aed6..f46dbc56ab824 100644
--- a/src/vxworks/mod.rs
+++ b/src/vxworks/mod.rs
@@ -1941,25 +1941,7 @@ pub fn posix_memalign(memptr: *mut *mut ::c_void, align: ::size_t, size: ::size_
     }
 }
 
-cfg_if! {
-    if #[cfg(libc_core_cvoid)] {
-        pub use ::ffi::c_void;
-    } else {
-        // Use repr(u8) as LLVM expects `void*` to be the same as `i8*` to help
-        // enable more optimization opportunities around it recognizing things
-        // like malloc/free.
-        #[repr(u8)]
-        #[allow(missing_copy_implementations)]
-        #[allow(missing_debug_implementations)]
-        pub enum c_void {
-            // Two dummy variants so the #[repr] attribute can be used.
-            #[doc(hidden)]
-            __variant1,
-            #[doc(hidden)]
-            __variant2,
-        }
-    }
-}
+pub use ::ffi::c_void;
 
 cfg_if! {
     if #[cfg(target_arch = "aarch64")] {
diff --git a/src/windows/gnu/mod.rs b/src/windows/gnu/mod.rs
index 3e7d38b8e83c6..99b38c4172f1c 100644
--- a/src/windows/gnu/mod.rs
+++ b/src/windows/gnu/mod.rs
@@ -15,9 +15,5 @@ extern "C" {
     pub fn wmemchr(cx: *const ::wchar_t, c: ::wchar_t, n: ::size_t) -> *mut ::wchar_t;
 }
 
-cfg_if! {
-    if #[cfg(libc_align)] {
-        mod align;
-        pub use self::align::*;
-    }
-}
+mod align;
+pub use self::align::*;
\ No newline at end of file
diff --git a/src/windows/mod.rs b/src/windows/mod.rs
index 196f1f2e4b743..c4d8ee33b85d9 100644
--- a/src/windows/mod.rs
+++ b/src/windows/mod.rs
@@ -568,25 +568,7 @@ extern "system" {
     pub fn socket(af: ::c_int, socket_type: ::c_int, protocol: ::c_int) -> SOCKET;
 }
 
-cfg_if! {
-    if #[cfg(libc_core_cvoid)] {
-        pub use ::ffi::c_void;
-    } else {
-        // Use repr(u8) as LLVM expects `void*` to be the same as `i8*` to help
-        // enable more optimization opportunities around it recognizing things
-        // like malloc/free.
-        #[repr(u8)]
-        #[allow(missing_copy_implementations)]
-        #[allow(missing_debug_implementations)]
-        pub enum c_void {
-            // Two dummy variants so the #[repr] attribute can be used.
-            #[doc(hidden)]
-            __variant1,
-            #[doc(hidden)]
-            __variant2,
-        }
-    }
-}
+pub use ::ffi::c_void;
 
 cfg_if! {
     if #[cfg(all(target_env = "gnu"))] {
diff --git a/src/xous.rs b/src/xous.rs
index e6c0c2573d07d..78ac3f10e000e 100644
--- a/src/xous.rs
+++ b/src/xous.rs
@@ -28,22 +28,4 @@ pub type wchar_t = u32;
 pub const INT_MIN: c_int = -2147483648;
 pub const INT_MAX: c_int = 2147483647;
 
-cfg_if! {
-    if #[cfg(libc_core_cvoid)] {
-        pub use ::ffi::c_void;
-    } else {
-        // Use repr(u8) as LLVM expects `void*` to be the same as `i8*` to help
-        // enable more optimization opportunities around it recognizing things
-        // like malloc/free.
-        #[repr(u8)]
-        #[allow(missing_copy_implementations)]
-        #[allow(missing_debug_implementations)]
-        pub enum c_void {
-            // Two dummy variants so the #[repr] attribute can be used.
-            #[doc(hidden)]
-            __variant1,
-            #[doc(hidden)]
-            __variant2,
-        }
-    }
-}
+pub use ::ffi::c_void;
\ No newline at end of file