Auto merge of #99624 - vincenzopalazzo:macros/unix_error, r=Amanieu

promote debug_assert to assert when possible and useful

This PR fixed a very old issue #94705 to clarify and improve the POSIX error checking, and some of the checks are skipped because can have no benefit, but I'm sure that this can open some interesting discussion.

Fixes #94705

cc: `@tavianator`
cc: `@cuviper`

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

@@ -687,7 +687,11 @@ impl Iterator for ReadDir {
 impl Drop for Dir {
     fn drop(&mut self) {
         let r = unsafe { libc::closedir(self.0) };
-        debug_assert_eq!(r, 0);
+        assert!(
+            r == 0 || crate::io::Error::last_os_error().kind() == crate::io::ErrorKind::Interrupted,
+            "unexpected error during closedir: {:?}",
+            crate::io::Error::last_os_error()
+        );
     }
 }
 

library/std/src/sys/unix/locks/pthread_condvar.rs

@@ -172,7 +172,7 @@ impl Condvar {
         let mut sys_now = libc::timeval { tv_sec: 0, tv_usec: 0 };
         let stable_now = Instant::now();
         let r = libc::gettimeofday(&mut sys_now, ptr::null_mut());
-        debug_assert_eq!(r, 0);
+        assert_eq!(r, 0, "unexpected error: {:?}", crate::io::Error::last_os_error());
 
         let nsec = dur.subsec_nanos() as libc::c_long + (sys_now.tv_usec * 1000) as libc::c_long;
         let extra = (nsec / 1_000_000_000) as libc::time_t;