std::unix::fs: removing, now useless, layers predating macOs 10.10.

fdopendir, openat and unlinkat are available since yosemite but we
support sierra as minimum.

library/std/src/sys/pal/unix/fs.rs

@@ -2010,56 +2010,10 @@ mod remove_dir_impl {
  use crate::sys::common::small_c_string::run_path_with_cstr;
  use crate::sys::{cvt, cvt_r};
 
- #[cfg(not(any(
- all(target_os = "linux", target_env = "gnu"),
- all(target_os = "macos", not(target_arch = "aarch64"))
- )))]
+ #[cfg(not(all(target_os = "linux", target_env = "gnu")))]
  use libc::{fdopendir, openat, unlinkat};
  #[cfg(all(target_os = "linux", target_env = "gnu"))]
  use libc::{fdopendir, openat64 as openat, unlinkat};
- #[cfg(all(target_os = "macos", not(target_arch = "aarch64")))]
- use macos_weak::{fdopendir, openat, unlinkat};
-
- #[cfg(all(target_os = "macos", not(target_arch = "aarch64")))]
- mod macos_weak {
- use crate::sys::weak::weak;
- use libc::{c_char, c_int, DIR};
-
- fn get_openat_fn() -> Option<unsafe extern "C" fn(c_int, *const c_char, c_int) -> c_int> {
- weak!(fn openat(c_int, *const c_char, c_int) -> c_int);
- openat.get()
- }
-
- pub fn has_openat() -> bool {
- get_openat_fn().is_some()
- }
-
- pub unsafe fn openat(dirfd: c_int, pathname: *const c_char, flags: c_int) -> c_int {
- get_openat_fn().map(|openat| openat(dirfd, pathname, flags)).unwrap_or_else(|| {
- crate::sys::pal::unix::os::set_errno(libc::ENOSYS);
- -1
- })
- }
-
- pub unsafe fn fdopendir(fd: c_int) -> *mut DIR {
- #[cfg(all(target_os = "macos", target_arch = "x86"))]
- weak!(fn fdopendir(c_int) -> *mut DIR, "fdopendir$INODE64$UNIX2003");
- #[cfg(all(target_os = "macos", target_arch = "x86_64"))]
- weak!(fn fdopendir(c_int) -> *mut DIR, "fdopendir$INODE64");
- fdopendir.get().map(|fdopendir| fdopendir(fd)).unwrap_or_else(|| {
- crate::sys::pal::unix::os::set_errno(libc::ENOSYS);
- crate::ptr::null_mut()
- })
- }
-
- pub unsafe fn unlinkat(dirfd: c_int, pathname: *const c_char, flags: c_int) -> c_int {
- weak!(fn unlinkat(c_int, *const c_char, c_int) -> c_int);
- unlinkat.get().map(|unlinkat| unlinkat(dirfd, pathname, flags)).unwrap_or_else(|| {
- crate::sys::pal::unix::os::set_errno(libc::ENOSYS);
- -1
- })
- }
- }
 
  pub fn openat__dironly(parent_fd: Option<RawFd>, p: &CStr) -> io::Result<OwnedFd> {
  let fd = cvt_r(|| unsafe {
@@ -2172,19 +2126,7 @@ mod remove_dir_impl {
  }
  }
 
- #[cfg(not(all(target_os = "macos", not(target_arch = "aarch64"))))]
  pub fn remove_dir_all(p: &Path) -> io::Result<()> {
  remove_dir_all_modern(p)
  }
-
- #[cfg(all(target_os = "macos", not(target_arch = "aarch64")))]
- pub fn remove_dir_all(p: &Path) -> io::Result<()> {
- if macos_weak::has_openat() {
- // openat() is available with macOS 10.10+, just like unlinkat() and fdopendir()
- remove_dir_all_modern(p)
- } else {
- // fall back to classic implementation
- crate::sys_common::fs::remove_dir_all(p)
- }
- }
 }