common: fix some warnings

common/list.c

@@ -205,7 +205,6 @@ void APP_CC
 list_dump_items(struct list* self)
 {
   int index;
-  tbus item;
 
   if (self->count == 0)
   {

common/os_calls.c

@@ -570,7 +570,11 @@ g_write_ip_address(int rcv_sck, char* ip_address, int bytes)
 {
   struct sockaddr_in s;
   struct in_addr in;
+#if defined(_WIN32)
   int len;
+#else
+  unsigned int len;
+#endif
   int ip_port;
   int ok;