musl: Decommonize definition of fanotify_event_metadata

musl has its own definition of the fanotify_event_metadata
struct and doesn't use the one from the Linux kernel.

The difference here is that musl's mask field has the type
unsigned long long, while the kernel uses __u64.

This currently causes libc-test to fail to compile on musl targets.

Linux: https://github.com/torvalds/linux/blob/master/include/uapi/linux/fanotify.h#L143
musl: https://git.musl-libc.org/cgit/musl/tree/include/sys/fanotify.h#n15

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

Author: Gelbpunkt

src/unix/linux_like/linux/mod.rs

@@ -1220,6 +1220,7 @@ s! {
         size: [u8; crate::__SIZEOF_PTHREAD_BARRIERATTR_T],
     }
 
+    #[cfg(not(target_env = "musl"))]
     #[repr(align(8))]
     pub struct fanotify_event_metadata {
         pub event_len: __u32,

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

@@ -122,6 +122,17 @@ impl siginfo_t {
 }
 
 s! {
+    #[repr(align(8))]
+    pub struct fanotify_event_metadata {
+        pub event_len: c_uint,
+        pub vers: c_uchar,
+        pub reserved: c_uchar,
+        pub metadata_len: c_ushort,
+        pub mask: c_ulonglong,
+        pub fd: c_int,
+        pub pid: c_int,
+    }
+
     // FIXME(1.0): This should not implement `PartialEq`
     #[allow(unpredictable_function_pointer_comparisons)]
     pub struct sigaction {