Timeout slow ares name lookups. This is based on the patch brought by

{

  CURLcode rc=CURLE_OK;

  struct SessionHandle *data = conn->data;

  struct timeval now = Curl_tvnow();

  bool timedout = FALSE;

  long timeout = 300; /* default name resolve timeout in seconds */

  long elapsed = 0; /* time taken so far */

  /* now, see if there's a connect timeout or a regular timeout to

     use instead of the default one */

  if(conn->data->set.connecttimeout)

    timeout = conn->data->set.connecttimeout;

  else if(conn->data->set.timeout)

    timeout = conn->data->set.timeout;

  /* Wait for the name resolve query to complete. */

  while (1) {

    int nfds=0;

    fd_set read_fds, write_fds;

    struct timeval *tvp, tv;

    struct timeval *tvp, tv, store;

    int count;

    store.tv_sec = timeout - elapsed;

    store.tv_usec = 0;

    FD_ZERO(&read_fds);

    FD_ZERO(&write_fds);

    nfds = ares_fds(data->state.areschannel, &read_fds, &write_fds);

    if (nfds == 0)

      break;

    tvp = ares_timeout(data->state.areschannel,

                       NULL, /* pass in our maximum time here */

                       &tv);

                       &store, &tv);

    count = select(nfds, &read_fds, &write_fds, NULL, tvp);

    if (count < 0 && errno != EINVAL)

      break;

    else if(!count) {

      /* timeout */

      timedout = TRUE;

      break;

    }

    ares_process(data->state.areschannel, &read_fds, &write_fds);

    elapsed = Curl_tvdiff(Curl_tvnow(), now)/1000; /* spent time */

  }

  /* Operation complete, if the lookup was successful we now have the entry

  if(!conn->async.dns) {

    /* a name was not resolved */

    if(conn->async.done) {

    if(timedout) {

      failf(data, "Resolving host timed out: %s", conn->name);

      rc = CURLE_OPERATION_TIMEDOUT;

    }

    else if(conn->async.done) {

      failf(data, "Could not resolve host: %s", conn->name);

      rc = CURLE_COULDNT_RESOLVE_HOST;

    }