Fix sparse warnings: non-ANSI function declarations, 0 used as pointer
diff --git a/extensions/libipt_REJECT.c b/extensions/libipt_REJECT.c
index 4af3713..90ec163 100644
--- a/extensions/libipt_REJECT.c
+++ b/extensions/libipt_REJECT.c
@@ -51,7 +51,7 @@
 };
 
 static void
-print_reject_types()
+print_reject_types(void)
 {
 	unsigned int i;
 
@@ -81,8 +81,8 @@
 }
 
 static const struct option opts[] = {
-	{ "reject-with", 1, 0, '1' },
-	{ 0 }
+	{ "reject-with", 1, NULL, '1' },
+	{ }
 };
 
 /* Allocate and initialize the target. */