Fix test compilation with restricted feature sets.

Add `cfg`s to fix build errors.

Author: sunfishcode

tests/event/select.rs

@@ -82,6 +82,7 @@ fn test_select_with_pipes() {
 }
 
 #[cfg(feature = "pipe")]
+#[cfg(feature = "process")]
 #[cfg(not(windows))]
 #[test]
 #[serial] // for `setrlimit` usage
@@ -271,6 +272,7 @@ fn test_select_with_sockets() {
 // Like `test_select_with_sockets` but test with the maximum permitted
 // fd value.
 #[cfg(feature = "net")]
+#[cfg(feature = "process")]
 #[cfg(not(windows))] // for `dup2` usage
 #[test]
 #[serial] // for `setrlimit` usage, and `crate::init`

tests/fs/special.rs

@@ -1,3 +1,4 @@
+#[cfg(feature = "process")]
 #[cfg(not(target_os = "wasi"))]
 #[test]
 fn test_special_fds() {

tests/io_uring/register.rs

@@ -8,6 +8,7 @@ use rustix::io_uring::{
     io_uring_rsrc_update, io_uring_setup, IoringFeatureFlags, IoringRegisterFlags,
     IoringRegisterOp,
 };
+#[cfg(feature = "mm")]
 use rustix::mm::{MapFlags, ProtFlags};
 
 fn do_register<FD>(
@@ -122,6 +123,7 @@ fn test_io_uring_register_with() {
     register_result.unwrap();
 }
 
+#[cfg(feature = "mm")]
 #[test]
 fn io_uring_buf_ring_can_be_registered() {
     const ENTRIES: usize = 8;