[CFT] Mesa 18.0.0 update (mesa-libs, mesa-dri, libosmesa, clover)

[Jan Beich]

Mesa provides OpenGL drivers for Intel and AMD cards on FreeBSD. Recently,
a new major version was released. So far it was only tested by drm-next-kmod.
Can someone test on FreeBSD < 11.2 for regressions? In case of issues attach
/var/log/Xorg.0.log, run with LIBGL_DEBUG=verbose and check if 17.3.7 is also
affected.

I'd like to land the update in 2 weeks: 18.0.0 on /latest, 17.3.7 on /quarterly.

# Apply
$ fetch -qo /tmp/mesa-17.3.7.diff 'https://bugs.freebsd.org/bugzilla/attachment.cgi?id=191718'
$ fetch -qo /tmp/mesa-18.0.0.diff 'https://bugs.freebsd.org/bugzilla/attachment.cgi?id=191881'
$ patch -Efsp1 -i /tmp/mesa-17.3.7.diff -d /usr/ports
$ patch -Efsp1 -i /tmp/mesa-18.0.0.diff -d /usr/ports
$ make all deinstall install clean -C /usr/ports/graphics/mesa-libs
$ make all deinstall install clean -C /usr/ports/graphics/mesa-dri

# Undo
$ patch -REfsp1 -i /tmp/mesa-18.0.0.diff -d /usr/ports
$ patch -REfsp1 -i /tmp/mesa-17.3.7.diff -d /usr/ports
$ make all deinstall install clean -C /usr/ports/graphics/mesa-libs
$ make all deinstall install clean -C /usr/ports/graphics/mesa-dri

# Testing examples
- graphics/mesa-demos: glxgears, eglgears_x11
- multimedia/mpv: --hwdec=auto (VAAPI/VDPAU EGL interop)
- www/firefox: layers.acceleration.force-enabled=true (GPU compositing)
- https://forums.freebsd.org/threads/unreal-engine-4.65300/