split out ucred to a bits header

src/header/sys_socket/cbindgen.toml

@@ -16,10 +16,9 @@ after_includes = """
 #include <bits/socklen-t.h>  // for socklen_t
 #include <bits/ssize-t.h>    // for ssize_t from sys/types.h
 
-// Below required for Non-POSIX ucred struct
-#include <bits/gid-t.h> // for gid_t from sys/types.h
-#include <bits/pid-t.h> // for pid_t from sys/types.h
-#include <bits/uid-t.h> // for uid_t from sys/types.h
+#if defined(_GNU_SOURCE)
+#include <bits/ucred.h>      // for Non-POSIX ucred struct
+#endif
 """
 trailer = """
 #ifndef _RELIBC_BITS_SYS_SOCKET_H
@@ -61,7 +60,6 @@ prefix_with_name = true
 include = [
     "linger",
     "cmsghdr",
-    "ucred"
 ]
 
 [export.rename]

src/header/sys_socket/mod.rs

@@ -9,9 +9,7 @@ use crate::{
     header::{bits_safamily_t::sa_family_t, sys_uio::iovec},
     platform::{
         PalSocket, Sys,
-        types::{
-            c_char, c_int, c_long, c_uchar, c_uint, c_void, gid_t, pid_t, size_t, ssize_t, uid_t,
-        },
+        types::{c_char, c_int, c_long, c_uchar, c_uint, c_void, size_t, ssize_t},
     },
 };
 
@@ -61,22 +59,6 @@ pub struct cmsghdr {
     pub cmsg_type: c_int,
 }
 
-// TODO: `ucred` should be behind _GNU_SOURCE include guard
-/// Non-POSIX, see <https://www.man7.org/linux/man-pages/man7/unix.7.html>.
-///
-/// Represents UNIX credentials.
-#[repr(C)]
-#[derive(Clone, Debug)]
-// FIXME: CheckVsLibcCrate
-pub struct ucred {
-    /// Process ID of the sending process.
-    pub pid: pid_t,
-    /// User ID of the sending process.
-    pub uid: uid_t,
-    /// Group ID of the sending process.
-    pub gid: gid_t,
-}
-
 /// See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/sys_socket.h.html>.
 #[repr(C)]
 #[derive(Default, CheckVsLibcCrate)]