Why on earth this uses Linux syscalls on macOS?

--- .home/.cargo/macports/rustix-0.35.12/src/backend/libc/fs/syscalls.rs	2006-07-24 09:21:28.000000000 +0800
+++ .home/.cargo/macports/rustix-0.35.12/src/backend/libc/fs/syscalls.rs	2026-01-05 07:18:34.000000000 +0800
@@ -174,7 +174,7 @@
 /// Use a direct syscall (via libc) for `openat`.
 ///
 /// This is only currently necessary as a workaround for old glibc; see below.
-#[cfg(all(unix, target_env = "gnu"))]
+#[cfg(not(target_os = "macos"))]
 fn openat_via_syscall(
     dirfd: BorrowedFd<'_>,
     path: &CStr,
@@ -205,7 +205,7 @@
 ) -> io::Result<OwnedFd> {
     // Work around <https://sourceware.org/bugzilla/show_bug.cgi?id=17523>.
     // Basically old glibc versions don't handle O_TMPFILE correctly.
-    #[cfg(all(unix, target_env = "gnu"))]
+    #[cfg(not(target_os = "macos"))]
     if oflags.contains(OFlags::TMPFILE) && crate::backend::if_glibc_is_less_than_2_25() {
         return openat_via_syscall(dirfd, path, oflags, mode);
     }