diff --git a/appl/test/auditdns.c b/appl/test/auditdns.c
index 4f5b1dde5..3a79af45e 100644
--- a/appl/test/auditdns.c
+++ b/appl/test/auditdns.c
@@ -40,6 +40,10 @@
 #include "resolve.h"
 #include "roken.h"
 
+#if (__STDC_VERSION__ - 0) < 199901L
+# define restrict /* empty */
+#endif
+
 struct rk_dns_reply *
 rk_dns_lookup(const char *domain, const char *type_name)
 {