lift setfsgid/setfsuid from Linux to non-bsd

Author: Mic92

libc-test/build.rs

@@ -190,7 +190,6 @@ fn main() {
         cfg.header("sys/msg.h");
         cfg.header("sys/shm.h");
         cfg.header("sys/user.h");
-        cfg.header("sys/fsuid.h");
         cfg.header("sys/timerfd.h");
         cfg.header("shadow.h");
         if !emscripten {
@@ -212,6 +211,7 @@ fn main() {
         cfg.header("sched.h");
         cfg.header("sys/epoll.h");
         cfg.header("sys/eventfd.h");
+        cfg.header("sys/fsuid.h");
         cfg.header("sys/prctl.h");
         cfg.header("sys/sendfile.h");
         cfg.header("sys/signalfd.h");

src/unix/notbsd/linux/mod.rs

@@ -1224,8 +1224,6 @@ extern {
                              riovcnt: ::c_ulong,
                              flags: ::c_ulong) -> isize;
     pub fn reboot(how_to: ::c_int) -> ::c_int;
-    pub fn setfsgid(gid: ::gid_t) -> ::c_int;
-    pub fn setfsuid(uid: ::uid_t) -> ::c_int;
 
     // Not available now on Android
     pub fn mkfifoat(dirfd: ::c_int, pathname: *const ::c_char,

src/unix/notbsd/mod.rs

@@ -970,6 +970,8 @@ extern {
                   options: ::c_int) -> ::c_int;
     pub fn setreuid(ruid: ::uid_t, euid: ::uid_t) -> ::c_int;
     pub fn setregid(rgid: ::gid_t, egid: ::gid_t) -> ::c_int;
+    pub fn setfsgid(gid: ::gid_t) -> ::c_int;
+    pub fn setfsuid(uid: ::uid_t) -> ::c_int;
     pub fn getresuid(ruid: *mut ::uid_t, euid: *mut ::uid_t,
                      suid: *mut ::uid_t) -> ::c_int;
     pub fn getresgid(rgid: *mut ::gid_t, egid: *mut ::gid_t,