Update xctoolchain to latest.

nlutsenko · nlutsenko · commit 62aa4e360317 · 2015-12-10T11:38:25.000-08:00
diff --git a/Vendor/xctoolchain b/Vendor/xctoolchain
@@ -1 +1 @@
-Subproject commit 5b3d0d4db6cbbe3e5a6f58b56f82c2f5cad399cb
+Subproject commit e8aafbd44b087d4645169d213d463986a40b2a37
