HEADS-UP: virtual_oss in base

From: Christos Margiolis <christos_at_freebsd.org>
Date: Tue, 30 Sep 2025 15:44:40 UTC
As of 9cab9fde5eda ("virtual_oss: Port to base") [1], we have
virtual_oss in the base system. Quoting from RELNOTES [2] to avoid
repeating myself:

	virtual_oss is imported to base. The audio/virtual_oss port will
	stop being built from FreeBSD 15.0 onwards.

	Regarding user-facing changes, the only practical difference is
	the installation process. Everything is provided by the base
	system, except for the following optional components, which can
	be installed from ports:

	* sndio backend support: audio/virtual_oss_sndio
	* bluetooth backend support: audio/virtual_oss_bluetooth
	* virtual_equalizer(8): audio/virtual_oss_equalizer

	Apart from that, virtual_oss should work as expected. Users of
	virtual_oss can uninstall audio/virtual_oss and instead use the
	base system version from now on.

The commits for the ports can be found here: [3][4][5]. In the next days
I will also MFC virtual_oss to stable/15, so that it ships with
15.0-RELEASE.

[1] https://cgit.freebsd.org/src/commit/?id=9cab9fde5edad9b409dd2317a2aec7815e6d6bed
[2] https://cgit.freebsd.org/src/commit/?id=c457acb4ee821cf015930a94f52c3870786468a7
[3] https://cgit.freebsd.org/ports/commit/?id=a9bbba1949a79c419d88e64a280e56c0cc8131fc
[4] https://cgit.freebsd.org/ports/commit/?id=35215c174c450b6e7dfd2490334f7887b7c24710
[5] https://cgit.freebsd.org/ports/commit/?id=2dcc66e8c6c4b92a3278ea874b41e4b81ae441ed