musl: powerpc64: Decommonize definition of shmid_ds

powerpc64 is the only 64-bit target that doesn't use the generic
definition for these in musl.

See https://git.musl-libc.org/cgit/musl/tree/arch/powerpc64/bits/shm.h#n3

Signed-off-by: Jens Reidel <adrian@travitia.xyz>

Author: Gelbpunkt

src/unix/linux_like/linux/musl/b64/mod.rs

@@ -17,6 +17,8 @@ s! {
         __val: [c_ulong; 16],
     }
 
+    // PowerPC implementation is special, see the subfolder.
+    #[cfg(not(target_arch = "powerpc64"))]
     pub struct shmid_ds {
         pub shm_perm: crate::ipc_perm,
         pub shm_segsz: size_t,

src/unix/linux_like/linux/musl/b64/powerpc64.rs

@@ -50,6 +50,18 @@ s! {
         __reserved: [c_long; 3],
     }
 
+    pub struct shmid_ds {
+        pub shm_perm: crate::ipc_perm,
+        pub shm_atime: crate::time_t,
+        pub shm_dtime: crate::time_t,
+        pub shm_ctime: crate::time_t,
+        pub shm_segsz: size_t,
+        pub shm_cpid: crate::pid_t,
+        pub shm_lpid: crate::pid_t,
+        pub shm_nattch: c_ulong,
+        __unused: [c_ulong; 2],
+    }
+
     pub struct ipc_perm {
         #[cfg(musl_v1_2_3)]
         pub __key: crate::key_t,