ci: Add an x86_64-apple job

I'm not sure why this was missing: possibly because it was only
previously only possible to test with macos-13. GHA now has
macos-15-intel which makes this easier, so add the job back.

(backport <rust-lang#4777>)
(cherry picked from commit eb88448)

Author: tgross35

.github/workflows/ci.yaml

@@ -204,6 +204,8 @@ jobs:
           - target: wasm32-unknown-emscripten
           - target: wasm32-wasip1
           - target: wasm32-wasip2
+          - target: x86_64-apple-darwin
+            os: macos-15-intel
           - target: x86_64-linux-android
           # FIXME: Exec format error (os error 8)
           # - target: x86_64-unknown-linux-gnux32

libc-test/build.rs

@@ -317,7 +317,7 @@ fn test_apple(target: &str) {
         (x86_64, "crt_externs.h"),
     );
 
-    cfg.skip_struct(|s| {
+    cfg.skip_struct(move |s| {
         match s.ident() {
             // FIXME(union): actually a union
             "sigval" => true,
@@ -326,6 +326,9 @@ fn test_apple(target: &str) {
             // it is a moving target, changing through versions
             // also contains bitfields members
             "tcp_connection_info" => true,
+
+            // FIXME(macos): The size is changed in recent macOSes.
+            "malloc_introspection_t" if x86_64 => true,
             _ => false,
         }
     });
@@ -351,6 +354,8 @@ fn test_apple(target: &str) {
         match func.ident() {
             // FIXME: https://github.com/rust-lang/libc/issues/1272
             "execv" | "execve" | "execvp" => true,
+            // close calls the close_nocancel system call on x86
+            "close" if x86_64 => true,
             // FIXME(1.0): std removed libresolv support: https://github.com/rust-lang/rust/pull/102766
             "res_init" => true,
             _ => false,