rollup merge of #20568: huonw/ungate-AT-globs

These aren't in their final form, but are all aiming to be part of 1.0, so at the very least encouraging usage now to find the bugs is nice.

Also, the widespread roll-out of associated types in the standard library indicates they're getting good, and it's lame to have to activate a feature in essentially every crate ever.

src/librustc_llvm/lib.rs

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