std: allow weak in item position on Apple platforms

Author: joboet

library/std/src/sys/fd/unix.rs

@@ -326,9 +326,9 @@ impl FileDesc {
         );
 
         match preadv.get() {
-            Some(preadv) => {
+            Some(read) => {
                 let ret = cvt(unsafe {
-                    preadv(
+                    read(
                         self.as_raw_fd(),
                         bufs.as_mut_ptr() as *mut libc::iovec as *const libc::iovec,
                         cmp::min(bufs.len(), max_iov()) as libc::c_int,
@@ -532,9 +532,9 @@ impl FileDesc {
         );
 
         match pwritev.get() {
-            Some(pwritev) => {
+            Some(read) => {
                 let ret = cvt(unsafe {
-                    pwritev(
+                    read(
                         self.as_raw_fd(),
                         bufs.as_ptr() as *const libc::iovec,
                         cmp::min(bufs.len(), max_iov()) as libc::c_int,

library/std/src/sys/pal/unix/weak/dlsym.rs

@@ -8,8 +8,9 @@ use crate::{mem, ptr};
 mod tests;
 
 pub(crate) macro weak {
-    (fn $name:ident($($param:ident : $t:ty),* $(,)?) -> $ret:ty;) => (
-        static DLSYM: DlsymWeak<unsafe extern "C" fn($($t),*) -> $ret> = {
+    ($v:vis fn $name:ident($($param:ident : $t:ty),* $(,)?) -> $ret:ty;) => {
+        #[allow(non_upper_case_globals)]
+        $v static $name: DlsymWeak<unsafe extern "C" fn($($t),*) -> $ret> = {
             let Ok(name) = CStr::from_bytes_with_nul(concat!(stringify!($name), '\0').as_bytes()) else {
                 panic!("symbol name may not contain NUL")
             };
@@ -20,9 +21,7 @@ pub(crate) macro weak {
             // the function pointer be unsafe.
             unsafe { DlsymWeak::new(name) }
         };
-
-        let $name = &DLSYM;
-    )
+    }
 }
 
 pub(crate) struct DlsymWeak<F> {

library/std/src/sys/pal/unix/weak/tests.rs

@@ -11,8 +11,8 @@ fn weak_existing() {
         fn strlen(cs: *const c_char) -> usize;
     }
 
-    let strlen = strlen.get().unwrap();
-    assert_eq!(unsafe { strlen(TEST_STRING.as_ptr()) }, TEST_STRING.count_bytes());
+    let len = strlen.get().unwrap();
+    assert_eq!(unsafe { len(TEST_STRING.as_ptr()) }, TEST_STRING.count_bytes());
 }
 
 #[test]