Auto merge of rust-lang#802 - Mic92:setfsuid, r=alexcrichton

add setfsgid/setfsuid on Linux

Author: bors

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 {
@@ -241,6 +240,8 @@ fn main() {
     }
 
     if linux || android {
+        cfg.header("sys/fsuid.h");
+
         // DCCP support
         if !uclibc && !musl && !emscripten {
             cfg.header("linux/dccp.h");

src/unix/notbsd/android/mod.rs

@@ -1050,6 +1050,8 @@ extern {
                     in_fd: ::c_int,
                     offset: *mut off_t,
                     count: ::size_t) -> ::ssize_t;
+    pub fn setfsgid(gid: ::gid_t) -> ::c_int;
+    pub fn setfsuid(uid: ::uid_t) -> ::c_int;
     pub fn sigsuspend(mask: *const ::sigset_t) -> ::c_int;
     #[cfg_attr(target_os = "solaris", link_name = "__posix_getgrgid_r")]
     pub fn getgrgid_r(uid: ::uid_t,