diff --git a/bin/tests/system/rsabigexponent/bigkey.c b/bin/tests/system/rsabigexponent/bigkey.c
index 69607e5801..9f3d573b33 100644
--- a/bin/tests/system/rsabigexponent/bigkey.c
+++ b/bin/tests/system/rsabigexponent/bigkey.c
@@ -16,9 +16,10 @@
 
 /* $Id$ */
 
-#if defined(OPENSSL) || defined(PKCS11CRYPTO)
 #include <config.h>
 
+#if defined(OPENSSL) || defined(PKCS11CRYPTO)
+
 #include <stdio.h>
 #include <stdlib.h>
 
@@ -249,6 +250,8 @@ main(int argc, char **argv) {
 #include <stdio.h>
 #include <stdlib.h>
 
+#include <isc/util.h>
+
 int
 main(int argc, char **argv) {
 	UNUSED(argc);