diff --git a/include/time.h b/include/time.h
index 642d68c4e..bfc2ac435 100644
--- a/include/time.h
+++ b/include/time.h
@@ -39,9 +39,8 @@
 
 
 /* NULL pointer */
-#ifndef _HAVE_NULL
-#define NULL    0
-#define _HAVE_NULL
+#ifndef NULL
+#define NULL ((void *) 0)
 #endif
 
 /* size_t is needed */