Index: include/__config
===================================================================
--- include/__config
+++ include/__config
@@ -554,6 +554,15 @@
 
 #endif // __clang__ || __GNUC__ || _MSC_VER || __IBMCPP__
 
+#define _LIBCPP_BEGIN_NAMESPACE_INTERNAL namespace __libcpp_internal _LIBCPP_HIDDEN {
+#define _LIBCPP_END_NAMESPACE_INTERNAL }
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+  _LIBCPP_BEGIN_NAMESPACE_INTERNAL
+  _LIBCPP_END_NAMESPACE_INTERNAL
+  using namespace __libcpp_internal;
+_LIBCPP_END_NAMESPACE_STD
+
 #ifdef _LIBCPP_HAS_NO_UNICODE_CHARS
 typedef unsigned short char16_t;
 typedef unsigned int   char32_t;