rollup merge of #23598: brson/gate

Conflicts:
	src/compiletest/compiletest.rs
	src/libcollections/lib.rs
	src/librustc_back/lib.rs
	src/libserialize/lib.rs
	src/libstd/lib.rs
	src/libtest/lib.rs
	src/test/run-make/rustdoc-default-impl/foo.rs
	src/test/run-pass/env-home-dir.rs

src/librustdoc/lib.rs

@@ -52,6 +52,7 @@ extern crate rustc_back;
 extern crate serialize;
 extern crate syntax;
 extern crate "test" as testing;
+extern crate unicode;
 #[macro_use] extern crate log;
 
 extern crate "serialize" as rustc_serialize; // used by deriving