Add a way to store the results of an HTTP request when a slot finishes
so the results can be processed after the slot has been reused.
Signed-off-by: NNick Hengeveld <nickh@reactrix.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Move the static function get_curl_handle() around to make sure
its definition and declarations are seen by the compiler before
its first use.  Also remove an unused variable.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Move shared HTTP request functionality out of http-fetch and http-push,
and replace the two fwrite_buffer/fwrite_buffer_dynamic functions with
one fwrite_buffer function that does dynamic buffering.  Use slot
callbacks to process responses to fetch object transfer requests and
push transfer requests, and put all of http-push into an #ifdef check
for curl multi support.
Signed-off-by: NNick Hengeveld <nickh@reactrix.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>