Add cache support for APCu

[bretrzaun]

With PHP7 the userland caching of APC has been renamed to APCu. It would be nice if there would be a cache adapter for that too.

The needed modifications are minimal. Just replace the apc_ functions with apcu_.

[mzronek]

Have you considered using the apcu_bc extension for backwards compatibility?

https://pecl.php.net/package/apcu_bc

[voku]

I created a simple cache wrapper with support for apcu and e.g. for opcache-file-cache maybe we can use it here? -> https://github.com/voku/simple-cache

[glensc]

no, can't too high php requirement:

• https://github.com/voku/simple-cache/blob/4.0.3/composer.json

[voku]

I can also copy and past some of the caching classes, (e.g. apcu) most of the stuff should work also for PHP 5.x?