fix this for stdbuild only

libc-test/build.rs

@@ -416,6 +416,11 @@ fn main() {
             // which is absent in glibc, has to be defined.
             "__timeval" if linux => true,
 
+            // Fixed on stdbuild with repr(packed(4))
+            // Once repr_packed stabilizes we can fix this unconditionally
+            // and remove this check.
+            "kevent" | "shmid_ds" if apple && x86_64 => true,
+
             // This is actually a union, not a struct
             "sigval" => true,
 

src/lib.rs

@@ -87,7 +87,7 @@
 
 // Attributes needed when building as part of the standard library
 #![cfg_attr(feature = "stdbuild", feature(no_std, staged_api, custom_attribute, cfg_target_vendor))]
-#![cfg_attr(feature = "stdbuild", feature(link_cfg))]
+#![cfg_attr(feature = "stdbuild", feature(link_cfg, repr_packed))]
 #![cfg_attr(feature = "stdbuild", no_std)]
 #![cfg_attr(feature = "stdbuild", staged_api)]
 #![cfg_attr(feature = "stdbuild", allow(warnings))]

src/unix/bsd/apple/mod.rs

@@ -245,7 +245,7 @@ s! {
         pub f_reserved: [::uint32_t; 8],
     }
 
-    #[repr(packed(4))]
+    #[cfg_attr(feature = "stdbuild", repr(packed(4)))]
     pub struct kevent {
         pub ident: ::uintptr_t,
         pub filter: ::int16_t,
@@ -524,7 +524,7 @@ s! {
         pub _key: ::key_t,
     }
 
-    #[repr(packed(4))]
+    #[cfg_attr(feature = "stdbuild", repr(packed(4)))]
     pub struct shmid_ds {
         pub shm_perm: ipc_perm,
         pub shm_segsz: ::size_t,