Merge from rustc

Author: saethlin

tests/pass-dep/concurrency/tls_pthread_drop_order.rs

@@ -1,9 +1,9 @@
 //@ignore-target-windows: No pthreads on Windows
 //! Test that pthread_key destructors are run in the right order.
 //! Note that these are *not* used by actual `thread_local!` on Linux! Those use
-//! `thread_local_dtor::register_dtor` from the stdlib instead. In Miri this hits the fallback path
-//! in `register_dtor_fallback`, which uses a *single* pthread_key to manage a thread-local list of
-//! dtors to call.
+//! `destructors::register` from the stdlib instead. In Miri this ends up hitting
+//! the fallback path in `guard::key::enable`, which uses a *single* pthread_key
+//! to manage a thread-local list of dtors to call.
 
 use std::mem;
 use std::ptr;