diff --git a/config.h.in b/config.h.in
index e44e54e..66f214c 100644
--- a/config.h.in
+++ b/config.h.in
@@ -76,6 +76,9 @@
 /* Define if you have the vsprintf function.  */
 #undef HAVE_VSPRINTF
 
+/* Define if you have the <ansidecl.h> header file.  */
+#undef HAVE_ANSIDECL_H
+
 /* Define if you have the <arpa/inet.h> header file.  */
 #undef HAVE_ARPA_INET_H