diff --git a/libcxx/include/__algorithm/radix_sort.h b/libcxx/include/__algorithm/radix_sort.h
--- a/libcxx/include/__algorithm/radix_sort.h
+++ b/libcxx/include/__algorithm/radix_sort.h
@@ -29,6 +29,8 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
+#if _LIBCPP_STD_VER > 14
+
 inline void __variadic_expansion_dummy(initializer_list<int>) {}
 
 #define EXPAND_VARIADIC(expression) __variadic_expansion_dummy({(expression, 0)...})
@@ -261,6 +263,15 @@
 
 #undef EXPAND_VARIADIC
 
+#else // _LIBCPP_STD_VER > 14
+
+template <typename _RandomAccessIterator1, typename _RandomAccessIterator2, bool _B>
+bool __radix_sort(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2, _BoolConstant<_B>) {
+  return false;
+}
+
+#endif // _LIBCPP_STD_VER > 14
+
 _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS