Remove warning from the libraries.

This adds the int_uint feature to *every* library, whether or not it
needs it.

src/libcore/lib.rs

@@ -59,9 +59,10 @@
 #![no_std]
 #![allow(unknown_features, raw_pointer_derive)]
 #![cfg_attr(stage0, allow(unused_attributes))]
-#![feature(intrinsics, lang_items)]
+#![allow(unknown_features)] #![feature(intrinsics, lang_items)]
 #![feature(simd, unsafe_destructor, slicing_syntax)]
 #![feature(unboxed_closures)]
+#![allow(unknown_features)] #![feature(int_uint)]
 #![deny(missing_docs)]
 
 #[macro_use]