Implement apcu_inc() and apcu_dec() using atomic operations. This means that these functions no longer have to acquire a write lock. These functions will now wraparound on overflow, instead of saturating to a floating point value.
Make table header in apc.php sticky.
Fix compile warnings related to mktemp() usage.
Fix compatibility with PHP 8.0.
Fix required number of arguments for apcu_store() returned by Reflection.