diff --git a/libbb/libc5.c b/libbb/libc5.c
index d595fe30a..59c935e3d 100644
--- a/libbb/libc5.c
+++ b/libbb/libc5.c
@@ -9,7 +9,7 @@
 #include <unistd.h>
 
 
-#ifndef __dietlibc__ &&  __GNU_LIBRARY__ < 5
+#if ! defined __dietlibc__ &&  __GNU_LIBRARY__ < 5
 
 /*
  * Some systems already have updwtmp().  Some don't...  This is