Disable AAAA lookups in libcurl
IPv6, not IPv4, is the forward-looking version of IP, you know... IPv6 is sorry to see you go :-( But you can disable it.
If you are using libcURL then all you have to do is this:
curl_easy_setopt(easy_handle, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4);
However, are you worried about the time these extra AAAA requests take, or the extra network traffic? I would hope that the A and AAAA are done in parallel so you shouldn't need to worry about a delay.