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

add setfsgid/setfsuid on Linux

Author: bors

src/unix/notbsd/linux/mod.rs

@@ -1228,8 +1228,6 @@ 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,