=== Sound mixer improvements

Links: +
link:https://wiki.freebsd.org/SummerOfCode2021Projects/SoundMixerImprovements[GSoC 2021 project article] URL: link:https://wiki.freebsd.org/SummerOfCode2021Projects/SoundMixerImprovements[https://wiki.freebsd.org/SummerOfCode2021Projects/SoundMixerImprovements]

Contact: Christos Margiolis <christos@FreeBSD.org> +
Contact: Hans Petter Selasky <hselasky@FreeBSD.org>

This project is an attempt to improve the capabilities of the OSS sound mixer
on FreeBSD. This means a new mixer(3) library, a complete rewrite of mixer(8),
and updates to sound(4).

Development started during Google Summer of Code 2021, but will likely continue
independently.

Applied changes:

* Implement OSS mixer (un)muting ioctls in sound(4)
(link:https://cgit.freebsd.org/src/commit/?id=0f8dafb45859569aa36b63ca2bb4a1c35c970d1e[commit 0f8dafb45859]).
* Implement playback/recording mode sysctl
(link:https://cgit.freebsd.org/src/commit/?id=ed2196e5df0c8b5b81563d2fffdcb32bb7ebe966[commit ed2196e5df0c]).
* Implement mixer(3) and new version of mixer(8)
(link:https://cgit.freebsd.org/src/commit/?id=903873ce15600fc02a0ea42cbf888cff232b411d[commit 903873ce1560]).

Patches, comments and discussion are all welcome.