auto merge of #10312 : thestinger/rust/thread_local, r=alexcritchton

This provides a building block for fast thread-local storage. It does
not change the safety semantics of `static mut`.

Closes #10310

1 files changed, 2 insertions, 0 deletions

diff --git a/doc/rust.md b/doc/rust.md
index 4fca2b33696..852feef4651 100644
--- a/doc/rust.md
+++ b/doc/rust.md
@@ -1754,6 +1754,8 @@ names are effectively reserved. Some significant attributes include:
 * The `deriving` attribute, for automatically generating
   implementations of certain traits.
 * The `static_assert` attribute, for asserting that a static bool is true at compiletime
+* The `thread_local` attribute, for defining a `static mut` as a thread-local. Note that this is
+  only a low-level building block, and is not local to a *task*, nor does it provide safety.
 
 Other attributes may be added or removed during development of the language.