[RFC] HTTP/2 Server Push support in ext/curl

Hey folks, I'd like to introduce a new RFC for 7.1 that will add support for HTTP/2 Server Push to ext/curl. This is exposing new features from libcurl to user land, which means they must have the latest (in fact currently unreleased, due to a bugfix) version of libcurl. For those who are not aware, HTTP/2 support is growing rapidly, and is already available in 60% of browsers, Apache 2 (via mod_h2), nginx, and even IIS. The RFC can be seen here: https://wiki.php.net/rfc/curl_http2_push With the patch at: https://github.com/php/php-src/compare/master...dshafik:curl-http2-push The patch still needs some work, possibly a lot of work due to my inexperience with C. Specifically, there are some memory leaks I've managed to introduce with the headers array stuff (I'm pretty sure, lines 529-535[1]) and there is some duplicated code from interface.c (lines 454-523[2]) that I was unable to refactor out successfully to it's own function. Plus, on the whole it seems incredibly untidy to me. Feedback welcome! - Davey [1] https://github.com/php/php-src/compare/master...dshafik:curl-http2-push#diff-ab7a9164033bd55887d45d0a6cb837eeR529 [2] https://github.com/php/php-src/compare/master...dshafik:curl-http2-push#diff-ab7a9164033bd55887d45d0a6cb837eeR451