message: fix compile fail on 5.6
diff: @@ -985,6 +985,8 @@ PHP_FUNCTION(swoole_async_dns_lookup)
  static int process_stream_onRead(swReactor *reactor, swEvent *event)
  {
  + SWOOLE_GET_TSRMLS;
  +
  process_stream *ps = event->socket->object;
  char *buf = ps->buffer->str + ps->buffer->length;
  size_t len = ps->buffer->size - ps->buffer->length;
  