get rid of numerous gcc-4 warnings
diff --git a/iptables.c b/iptables.c
index 92c6c49..0bb2b03 100644
--- a/iptables.c
+++ b/iptables.c
@@ -484,7 +484,8 @@
 }
 
 static void
-add_command(int *cmd, const int newcmd, const int othercmds, int invert)
+add_command(unsigned int *cmd, const int newcmd, const int othercmds, 
+	    int invert)
 {
 	if (invert)
 		exit_error(PARAMETER_PROBLEM, "unexpected ! flag");