=== SIMD enhancements for aarch64

Links: +
link:https://www.youtube.com/live/OzX38cWdivc?si=VsMrEmT_IdKpjv7W&t=22070[EuroBSDCon 2024 presentation] URL: link:https://www.youtube.com/live/OzX38cWdivc?si=VsMrEmT_IdKpjv7W&t=22070[] +
link:http://fuz.su/~fuz/talks/eurobsdcon-str-talk.pdf[Slides from presentation (PDF)] URL: link:http://fuz.su/~fuz/talks/eurobsdcon-str-talk.pdf[] +
link:https://summerofcode.withgoogle.com/programs/2024/projects/TKRS35FA[Google Summer of Code (GSoC) project description] URL: link:https://summerofcode.withgoogle.com/programs/2024/projects/TKRS35FA[] +
link:https://man.freebsd.org/cgi/man.cgi?query=simd&sektion=7&manpath=FreeBSD+15.0-CURRENT[simd(7)] URL: link:https://man.freebsd.org/cgi/man.cgi?query=simd&sektion=7&manpath=FreeBSD+15.0-CURRENT[] +

Contact: Getz Mikalsen <getz@FreeBSD.org>

The porting effort of the SIMD enhanced libc string functions from amd64 to aarch64 has been successfully completed.
There are now optimized implementations for 16 libc string functions in addition to those with implementations already available as part of the ARM optimized subroutines library.
There is also a presentation regarding the general method for these methods from EuroBSDCon 2024 available on YouTube with a short description in the end of how the porting has been done with regards to the aarch64 architecture.

These enhancements significantly improve performance of string functions for all FreeBSD systems on the aarch64 platform.

The code is currently undergoing acceptance testing in the form of an exp-run building all the ports, once without and once with the patch set applied to see if it has caused any new failures.

Sponsor: Google LLC (GSoC 2024)