fix gcc warnings

Max Kellermann <max@duempel.org>
diff --git a/extensions/libxt_connlimit.c b/extensions/libxt_connlimit.c
index 31f9311..9e2137a 100644
--- a/extensions/libxt_connlimit.c
+++ b/extensions/libxt_connlimit.c
@@ -21,7 +21,7 @@
 static const struct option connlimit_opts[] = {
 	{"connlimit-above", 1, NULL, 'A'},
 	{"connlimit-mask",  1, NULL, 'M'},
-	{NULL},
+	{ .name = NULL }
 };
 
 static void connlimit_init(struct xt_entry_match *match)