Index: kernel/generic/include/stddef.h
===================================================================
--- kernel/generic/include/stddef.h	(revision 002fd5f375765c45f5e59bbc374e1418520abddf)
+++ kernel/generic/include/stddef.h	(revision 810a36f826940da51368fa25256693505fcaca5c)
@@ -38,7 +38,5 @@
 #include <arch/types.h>
 
-#ifndef NULL
-	#define NULL  ((void *) 0)
-#endif
+#include <_bits/NULL.h>
 
 #define offsetof(type,member) ((size_t) &(((type *) 0)->member))