diff --git a/include/cstddef b/include/cstddef
index efe0f61c7..8264a8b29 100644
--- a/include/cstddef
+++ b/include/cstddef
@@ -34,9 +34,11 @@ Types:
 */
 
 #include <__config>
+#define __need_NULL
 #define __need_ptrdiff_t
 #define __need_size_t
 #include <stddef.h>
+#include <stddef.h>
 
 #pragma GCC system_header