linux-musl: Specialize struct statfs64 for s390x

statfs64 is the same as statfs on musl-libc, so it needs the same
adjustment.

https://git.musl-libc.org/cgit/musl/tree/include/sys/statfs.h#n21

Author: neuschaefer

src/unix/linux_like/linux/musl/b64/s390x.rs

@@ -83,6 +83,21 @@ s! {
         pub f_flags: c_uint,
         pub f_spare: [c_uint; 4],
     }
+
+    pub struct statfs64 {
+        pub f_type: c_uint,
+        pub f_bsize: c_uint,
+        pub f_blocks: crate::fsblkcnt_t,
+        pub f_bfree: crate::fsblkcnt_t,
+        pub f_bavail: crate::fsblkcnt_t,
+        pub f_files: crate::fsfilcnt_t,
+        pub f_ffree: crate::fsfilcnt_t,
+        pub f_fsid: crate::fsid_t,
+        pub f_namelen: c_uint,
+        pub f_frsize: c_uint,
+        pub f_flags: c_uint,
+        pub f_spare: [c_uint; 4],
+    }
 }
 
 s_no_extra_traits! {

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

@@ -389,8 +389,8 @@ s! {
         pub f_spare: [c_ulong; 4],
     }
 
-    // MIPS implementation is special (see mips arch folders)
-    #[cfg(not(any(target_arch = "mips", target_arch = "mips64")))]
+    // MIPS/s390x implementation is special (see arch folders)
+    #[cfg(not(any(target_arch = "mips", target_arch = "mips64", target_arch = "s390x")))]
     pub struct statfs64 {
         pub f_type: c_ulong,
         pub f_bsize: c_ulong,