XCache integration made sense with PHP 5.6 and older versions. With
OPCache being available directly in the PHP it made less sense to enable
it as well. Also the upstream site doesn't seem to be maintained anymore.
The previous docs link isn't found on the php.net website but there is docs for APC
so this patch just updates to the current valid docs on the website.
- Explain what opcodes are
- Clarify the cache will check if the source code has changed
- How to verify cache is turned on
- Clarify naming (Opcache vs Zend OPcache vs Optimizer+ – hope I've got this right)
- fix missing PHP versions for APC in links (markdown problem)