Auto merge of rust-lang#760 - JayH5:linux-initgroups, r=alexcrichton

Linux/Android: re-add initgroups

This was removed in rust-lang#742

Author: bors

Diff for: src/unix/notbsd/android/mod.rs

@@ -1065,6 +1065,7 @@ extern {
                         group: ::gid_t,
                         groups: *mut ::gid_t,
                         ngroups: *mut ::c_int) -> ::c_int;
+    pub fn initgroups(user: *const ::c_char, group: ::gid_t) -> ::c_int;
     pub fn pthread_mutexattr_getpshared(attr: *const pthread_mutexattr_t,
                                         pshared: *mut ::c_int) -> ::c_int;
     #[cfg_attr(all(target_os = "macos", target_arch = "x86"),

Diff for: src/unix/notbsd/linux/mod.rs

@@ -1322,6 +1322,7 @@ extern {
                       buf: *mut ::c_char,
                       buflen: ::size_t,
                       result: *mut *mut ::group) -> ::c_int;
+    pub fn initgroups(user: *const ::c_char, group: ::gid_t) -> ::c_int;
     #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
                link_name = "pthread_sigmask$UNIX2003")]
     pub fn pthread_sigmask(how: ::c_int, set: *const sigset_t,

Diff for: src/unix/notbsd/mod.rs

@@ -997,4 +997,3 @@ cfg_if! {
     //             name: *mut ::c_char,
     //             termp: *const termios,
     //             winp: *const ::winsize) -> ::pid_t;
-    // pub fn initgroups(user: *const ::c_char, group: ::gid_t) -> ::c_int;