Ungate default type parameters.

These are in scope for 1.0, and this is good to e.g. find as many bugs
as possible.

src/librustc_llvm/lib.rs

@@ -24,6 +24,7 @@
 #![feature(globs)]
 #![feature(link_args)]
 #![feature(unboxed_closures)]
+#![feature(old_orphan_check)]
 
 extern crate libc;