Index: libcxx/include/__config
===================================================================
--- libcxx/include/__config
+++ libcxx/include/__config
@@ -793,7 +793,7 @@
 #define _LIBCPP_INLINE_VISIBILITY _LIBCPP_HIDE_FROM_ABI
 
 // Inline namespaces are available in Clang/GCC/MSVC regardless of C++ dialect.
-#define _LIBCPP_BEGIN_NAMESPACE_STD namespace std { inline namespace _LIBCPP_ABI_NAMESPACE {
+#define _LIBCPP_BEGIN_NAMESPACE_STD namespace std _LIBCPP_HIDDEN { inline namespace _LIBCPP_ABI_NAMESPACE {
 #define _LIBCPP_END_NAMESPACE_STD  } }
 #define _VSTD std::_LIBCPP_ABI_NAMESPACE
 _LIBCPP_BEGIN_NAMESPACE_STD _LIBCPP_END_NAMESPACE_STD