diff --git a/sysdeps/unix/sysv/aix/bits/types.h b/sysdeps/unix/sysv/aix/bits/types.h
index cd57291051..df75454af1 100644
--- a/sysdeps/unix/sysv/aix/bits/types.h
+++ b/sysdeps/unix/sysv/aix/bits/types.h
@@ -25,6 +25,7 @@
 
 #include <features.h>
 
+#define __need_NULL
 #define __need_size_t
 #include <stddef.h>