Expose build configuration via PECL

[bsacharski]

It would seem that many of build configuration options like --enable-memcached-igbinary , --enable-memcached-msgpack and so on are not exposed as a PECL configuration option. Maybe it would be wise to expose them in package.xml file so it's possible to configure them in a nice manner.

[sodabrew]

Interesting! I'm not familiar with these options. Thanks for suggesting. Looks like the relevant PECL docs are here: https://pear.php.net/manual/en/guide.developers.package2.pecl.php