diff --git a/lib/regex.c b/lib/regex.c
index 2eb7c11..2f90dde 100644
--- a/lib/regex.c
+++ b/lib/regex.c
@@ -613,7 +613,7 @@
 # include <stdio.h>
 
 /* It is useful to test things that ``must'' be true when debugging.  */
-# include <assert.h>
+# include "zassert.h"
 
 static int debug;