Add #[fundamental] annotations into libcore so that Sized and the

`Fn` traits are considered fundamental, along with `Box` (though that is
mostly for show; the real type is `~T` in the compiler).

src/liballoc/lib.rs

@@ -71,6 +71,8 @@
 #![feature(no_std)]
 #![no_std]
 #![feature(allocator)]
+#![feature(custom_attribute)]
+#![feature(fundamental)]
 #![feature(lang_items, unsafe_destructor)]
 #![feature(box_syntax)]
 #![feature(optin_builtin_traits)]