diff --git a/include/__config b/include/__config
index 2b590cc8d..adce0a6d0 100644
--- a/include/__config
+++ b/include/__config
@@ -148,22 +148,15 @@ typedef __char32_t char32_t;
 #define _LIBCPP_HAS_NO_TRAILING_RETURN
 #endif
 
-#if __has_feature(cxx_inline_namespaces)
+// Inline namespaces are available in Clang regardless of C++ dialect.
 #define _LIBCPP_BEGIN_NAMESPACE_STD namespace std {inline namespace _LIBCPP_NAMESPACE {
 #define _LIBCPP_END_NAMESPACE_STD  } }
 #define _STD std::_LIBCPP_NAMESPACE
 
 namespace std {
-inline namespace _LIBCPP_NAMESPACE {
+  inline namespace _LIBCPP_NAMESPACE {
+  }
 }
-using namespace _LIBCPP_NAMESPACE;
-}
-
-#else  // __has_feature(cxx_inline_namespaces)
-#define _LIBCPP_BEGIN_NAMESPACE_STD namespace std {
-#define _LIBCPP_END_NAMESPACE_STD }
-#define _STD std
-#endif  // __has_feature(cxx_inline_namespaces)
 
 #if !(__has_feature(cxx_constexpr))
 #define _LIBCPP_HAS_NO_CONSTEXPR