compile with old kernel, new userspace
diff --git a/extensions/libipt_rpc.c b/extensions/libipt_rpc.c
index f5d4c1a..7fb0586 100644
--- a/extensions/libipt_rpc.c
+++ b/extensions/libipt_rpc.c
@@ -89,7 +89,7 @@
 }
 
 
-static int k_atoi(char *string)
+static int k_atoi(signed char *string)
 {
 	unsigned int result = 0;
 	int maxoctet = IPT_RPC_CHAR_LEN;