Fixes
- PS Vita: servers reached by a hostname no longer stall with an endless
"timeout reached". libcurl was built with the synchronous name resolver, so
a DNS lookup issued from a background thread could not be bounded by any
timeout — the synchronous resolver can only abort a slowgetaddrinfo()via
SIGALRM, which libcurl arms on the main thread alone. A slow-to-resolve
hostname (e.g. a duckdns address) therefore hung every request indefinitely,
and raising the request-timeout setting had no effect; only a raw LAN IP,
which skips name resolution, worked. curl is now built with the threaded
resolver so lookups run in a worker thread the timeout can abandon, and
CURLOPT_NOSIGNALkeeps libcurl off signals on its background threads.