Changes with nginx 0.7.48 06 Apr 2009
*) Feature: the "proxy_cache_key" directive.
*) Bugfix: now nginx takes into account the "X-Accel-Expires",
"Expires", and "Cache-Control" header lines in a backend response.
*) Bugfix: now nginx caches responses for the GET requests only.
*) Bugfix: the "fastcgi_cache_key" directive was not inherited.
*) Bugfix: the $arg_... variables did not work with SSI subrequests.
Thanks to Maxim Dounin.
*) Bugfix: nginx could not be built with uclibc library.
Thanks to Timothy Redaelli.
*) Bugfix: nginx could not be built on OpenBSD; the bug had
appeared in 0.7.46.