diff --git a/config.h.in b/config.h.in
index 39b59f8..6fb2490 100644
--- a/config.h.in
+++ b/config.h.in
@@ -12,6 +12,18 @@
 /* Define to 1 if you have the `gethostbyname' function. */
 #undef HAVE_GETHOSTBYNAME
 
+/* Define to 1 if you have the <getopt.h> header file. */
+#undef HAVE_GETOPT_H
+
+/* Define to 1 if you have the `getopt_long' function. */
+#undef HAVE_GETOPT_LONG
+
+/* Define to 1 if you have the `inet_addr' function. */
+#undef HAVE_INET_ADDR
+
+/* Define to 1 if you have the `inet_aton' function. */
+#undef HAVE_INET_ATON
+
 /* Define to 1 if you have the `inet_ntoa' function. */
 #undef HAVE_INET_NTOA