rollup merge of #17666 : eddyb/take-garbage-out

Conflicts:
	src/libcollections/lib.rs
	src/libcore/lib.rs
	src/librustdoc/lib.rs
	src/librustrt/lib.rs
	src/libserialize/lib.rs
	src/libstd/lib.rs
	src/test/run-pass/issue-8898.rs

src/librustdoc/lib.rs

@@ -15,7 +15,7 @@
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 
-#![feature(globs, struct_variant, managed_boxes, macro_rules, phase)]
+#![feature(globs, struct_variant, macro_rules, phase)]
 
 extern crate arena;
 extern crate debug;