Fix mips fallout on new toolchain

Author: Alexander Polakov

src/unix/notbsd/linux/mips.rs

@@ -63,7 +63,7 @@ s! {
     }
 
     pub struct sigaction {
-        pub sa_flags: ::c_uint,
+        pub sa_flags: ::c_int,
         pub sa_sigaction: ::sighandler_t,
         pub sa_mask: sigset_t,
         _restorer: *mut ::c_void,
@@ -454,7 +454,7 @@ extern {
                        hostlen: ::socklen_t,
                        serv: *mut ::c_char,
                        sevlen: ::socklen_t,
-                       flags: ::c_uint) -> ::c_int;
+                       flags: ::c_int) -> ::c_int;
     pub fn eventfd(init: ::c_int, flags: ::c_int) -> ::c_int;
     pub fn ptrace(request: ::c_uint, ...) -> ::c_long;
 }