Update from 5.1.12 to 5.1.14

• Add LICNESE_FILE

Changelog:
5.1.14:

• Fixed GH #347: Disable slam defense by default.
• Fix potential issue with destruction of locks. This does not affect Linux, but might affect Windows and BSD.
• Use mutex instead of rwlock for shared memory allocator (if pthreads mutex available).
• Require only read-lock for apcu_cas(), by using atomic compare-and-swap.

5.1.13:

• Reimplement persistence logic using precise allocation rather than memory pools. This reduces

memory usage of cache entries, especially for small values, and improves performance of persisting
and unpersisting values.

• Fixed GH #335: Stampede protection is broken.
• Fixed GH #328: Segfault in apcu_key_info() if APCu is disabled.
• Generally make the behavior of functions if APCu is disabled more consistent.
• Fixed PHP bug #72980: Empty strings are now consistently allowed as cache keys.
• Optimized apcu_key_info() and apcu_cache_info() by using interned strings.
• Fix build against PHP master (PHP 7.4).
• Many changes to internal C APIs.

Sponsored by: Netzkommune GmbH