Change the default mesa configuration to use DRI3 rather than the older DRI2
interface. This should improve performance somewhat, and alleviates the need
for the FIXDRM option in x11-servers/xorg-server.
Remove the FIXDRM option from x11-servers/xorg-server.
Add an UPDATING entry for the change.
For users of graphics/drm-legacy-kmod or the base graphics drivers, this might
cause regressions. If you experience problems when running OpenGL applications
please force the use of the DRI2 backend by setting the LIBGL_DRI3_DISABLE
environment variable to 1 before starting any OpenGL application. This is
easiest done by adding it to your shell startup file or .xinitrc.
Add UPDATING entry for xorg-server, detailing the change of device
configuration backend.
PR: 196678, 244306 (for tracking)
121ae90af1