[PATCH] [libc++] Allow libc++ to be built on systems without POSIX threads

[Jon Roelofs]

================
Comment at: sources/cxx-stl/llvm-libc++/libcxx/include/__mutex_base:53
@@ -49,2 +52,3 @@
 };
+#endif // !_LIBCPP_SINGLE_THREADED
 
----------------
awong pointed out that it makes sense to exclude defer_lock_t and friends also,

so delete this line....

================
Comment at: sources/cxx-stl/llvm-libc++/libcxx/include/__mutex_base:269
@@ -264,2 +268,3 @@
 
+#if !_LIBCPP_SINGLE_THREADED
 class _LIBCPP_TYPE_VIS condition_variable
----------------
... and this one.

http://reviews.llvm.org/D3969