Create separate APC/APCu adapters.

[jlis]

Would it make sense to create a separate APC and APCu adapter? Currently this package is not usable with PHP 7 since the APC Adapter, which uses APCu methods, is relying on the symfony/polyfill-apcu package under the hood to provide compatibility for PHP 5.6 and APC.

Basically the current APC adapter could be copied and renamed to APCu and instead of apcu_ methods one shall use \apcu_ methods. This way the polyfill could remain.

[NoelDavies]

It worked for me - I just installed the apcu-bc extension which works perfectly. Not ideal to have more extensions - but hey :P