Auto merge of #2587 - rtzoeller:dfly_fallocate_fadvise, r=Amanieu

DragonFly supports posix_fallocate, stubs posix_fadvise

- https://github.com/DragonFlyBSD/DragonFlyBSD/blob/master/lib/libc/sys/posix_fallocate.2
- https://github.com/DragonFlyBSD/DragonFlyBSD/blob/master/lib/libc/stdlib/posix_fadvise.3

libc-test/semver/dragonfly.txt

@@ -1352,6 +1352,8 @@ openpty
 pause
 pipe2
 popen
+posix_fadvise
+posix_fallocate
 posix_madvise
 ppoll
 preadv

src/unix/bsd/freebsdlike/freebsd/mod.rs

@@ -3840,8 +3840,6 @@ extern "C" {
         sevp: *mut sigevent,
     ) -> ::c_int;
 
-    pub fn posix_fallocate(fd: ::c_int, offset: ::off_t, len: ::off_t) -> ::c_int;
-    pub fn posix_fadvise(fd: ::c_int, offset: ::off_t, len: ::off_t, advise: ::c_int) -> ::c_int;
     pub fn mkostemp(template: *mut ::c_char, flags: ::c_int) -> ::c_int;
     pub fn mkostemps(template: *mut ::c_char, suffixlen: ::c_int, flags: ::c_int) -> ::c_int;
 

src/unix/bsd/freebsdlike/mod.rs

@@ -1512,6 +1512,8 @@ extern "C" {
     pub fn newlocale(mask: ::c_int, locale: *const ::c_char, base: ::locale_t) -> ::locale_t;
     pub fn nl_langinfo_l(item: ::nl_item, locale: ::locale_t) -> *mut ::c_char;
     pub fn pipe2(fds: *mut ::c_int, flags: ::c_int) -> ::c_int;
+    pub fn posix_fallocate(fd: ::c_int, offset: ::off_t, len: ::off_t) -> ::c_int;
+    pub fn posix_fadvise(fd: ::c_int, offset: ::off_t, len: ::off_t, advise: ::c_int) -> ::c_int;
     pub fn ppoll(
         fds: *mut ::pollfd,
         nfds: ::nfds_t,