diff --git a/libcxx/include/__assert b/libcxx/include/__assert
--- a/libcxx/include/__assert
+++ b/libcxx/include/__assert
@@ -48,6 +48,10 @@
 # define _LIBCPP_ASSERT(expression, message) ((void)0)
 #endif
 
+#ifndef _PSTL_ASSERT
+#  define _PSTL_ASSERT(...) _LIBCPP_ASSERT((__VA_ARGS__), "")
+#endif
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 _LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_AVAILABILITY_ASSERTION_HANDLER