The implementation is based on the upstream PMurHash. The following
variants are implemented
- murmur3a, 32-bit hash
- murmur3c, 128-bit hash for x86
- murmur3f, 128-bit hash for x64
The custom seed support is not targeted by this implementation. It will
need a major change to the API, so then custom arguments can be passed
through `hash_init`. For now, the starting hash is always zero.
Fixes bug #68109, closes #6059
Signed-off-by: Anatol Belski <ab@php.net> Co-Developed-by: Michael Wallner <mike@php.net> Signed-off-by: Michael Wallner <mike@php.net>