Fix compile errors: some compilers don't like an enum and the namespace it is in to have the same name.

[SVN r23660]

libs/thread

@@ -1 +1 @@
-Subproject commit 921d4c24c2e6e9134efd1774751e88b07b0d4c1d
+Subproject commit 4cd6453cac8ce3b300fa6a81b01468edc7950899