/*
 * call-seq:
 *   Curl.asyncdns?                                   => true or false
 *
 * Returns true if the installed libcurl was built with support for
 * asynchronous name lookups, which allows more exact timeouts (even
 * on Windows) and less blocking when using the multi interface.
 * For libcurl versions < 7.10.7, always returns false.
 */
static VALUE ruby_curl_asyncdns_q(VALUE mod) {