audio/fossmixer: fix illegal instruction error on some hosts

Previously, configure script was passing certain optimization options
by default; now it is protected by --enable-native switch which users
have to specify explicitly:

  -C_FLAGS=$C_FLAGS" -O3 -ffast-math `/bin/sh ./build/opt.sh \"$CC\"
-march=native`"
  +C_FLAGS=$C_FLAGS" -O2"

Take one step further and replace -O2 with our default CFLAGS which are
essentially the same, but safer (https://blog.regehr.org/archives/1307).

We must, however, force -msse2 on i386 for the build to succeed there;
other architectures might or might not need similar treatment as well.

PR:		257520
Submitted by:	maintainer (who is also upstream author)

graphics/mesa-libs: Bump reverse deps for libglvnd

Per discussion with bapt on helping pkg handle the changing of these
deps and avoiding impossible upgrade senarios.

PR:		246767
Reviewed by:	manu, bapt
Approved by:	x11
Differential Revision:	https://reviews.freebsd.org/D30824

One more small cleanup, forgotten yesterday.
Reported by:	lwhsu

Remove # $FreeBSD$ from Makefiles.

audio/fossmixer: Update to 0.0.3

Update maintainer email address.

*While here*
Use SF macro in MASTER_SITES
Use USES=tar:xz instead of EXTRACT_SUFX
Remove redundant redefinition of WRKSRC

PR:		242088
Submitted by:	Jani Salonen <salojan@goto10.co> (maintainer)

Prefer graphics/ligvrsvg2-rust over graphics/librsvg2

- switch to the more modern version of librsvg2 on architectures
  supporting rust
- this will fix some graphical issues on these architectures

PR:		250276
Exp-run by:	antoine
Submitted by:	tobik
Differential Revision:	https://reviews.freebsd.org/D18878

Add USES=xorg USES=gl, ports categories a

Add USES=xorg, USES=gl and in a few cases USES=gnome to ports in categories
starting with 'a'.

New port audio/fossmixer: Graphical mixer application for OSS

FOSS Mixer is a graphical mixer application for FreeBSD to control OSS
audio backend. Mixer can be use to control audio levels, set recording
source, and it includes white noise generator for testing the audio
output. It is pretty much what mixer(1) does. FOSS Mixer does not need
third party user interface library, it runs on plain X11/OpenGL.

PR:		239929
Submitted by:	manwe@suomi24.fi