[i965] enable Gallium3D crocus driver

[Benjamin]

Starting with Mesa 21.2 an alternative driver for Intel hardware for Gen4 through Gen7 is available that is based on Gallium3D.

It provides new features (like the Gallium Nine state tracker) and improved performance in some scenarios. Since the driver is still experimental, it is no enabled by default but can be selected by setting the

    MESA_LOADER_DRIVER_OVERRIDE=crocus

environment variable.

Ubuntu does not enable the driver in it's mesa build, when selected I will just get this error message instead:

$ MESA_LOADER_DRIVER_OVERRIDE=crocus glxinfo
libGL error: MESA-LOADER: failed to open crocus: /usr/lib/dri/crocus_dri.so: cannot open shared object file: No such file or directory (search paths /usr/lib/x86_64-linux-gnu/dri:\$${ORIGIN}/dri:/usr/lib/dri, suffix _dri)
libGL error: failed to load driver: crocus
libGL error: MESA-LOADER: failed to open crocus: /usr/lib/dri/crocus_dri.so: cannot open shared object file: No such file or directory (search paths /usr/lib/x86_64-linux-gnu/dri:\$${ORIGIN}/dri:/usr/lib/dri, suffix _dri)
libGL error: failed to load driver: crocus

This is with Mesa 21.2.2 - libgl1-mesa-dri (21.2.2-1ubuntu1)

[Launchpad Janitor (janitor)]

This bug was fixed in the package mesa - 21.3.5-1ubuntu1

---------------
mesa (21.3.5-1ubuntu1) jammy; urgency=medium

  * Revert back to llvm-12, again.

 -- Timo Aaltonen <email address hidden> Wed, 09 Feb 2022 10:19:02 +0200