TODO: CURLOPT_RESOLVE for any port number

 1.5 get rid of PATH_MAX

 1.6 Modified buffer size approach

 1.7 Detect when called from within callbacks

 1.8 CURLOPT_RESOLVE for any port number

 1.9 Cache negative name resolves

 1.11 minimize dependencies with dynamicly loaded modules

 1.12 have form functions use CURL handle argument

 subsequently can add code within libcurl that returns error if called within

 callbacks for when that's not supported.

1.8 CURLOPT_RESOLVE for any port number

 This option allows applications to set a replacement IP address for a given

 host + port pair. Consider making support for providing a replacement address

 for the host name on all port numbers.

 See https://github.com/curl/curl/issues/1264

1.9 Cache negative name resolves

 A name resolve that has failed is likely to fail when made again within a

 Make sure we don't ever loop because of non-blocking sockets returning

 EWOULDBLOCK or similar. Blocking cases include:

 - Name resolves on non-windows unless c-ares is used

 - Name resolves on non-windows unless c-ares or the threaded resolver is used

 - HTTP proxy CONNECT operations

 - SOCKS proxy handshakes

 - file:// transfers