The dxcompiler is only used for 64 bit builds, because no official
32 bit implementation is distributed. This might change in the future
building the compiler ourselves and using vkd3d-shader to sign the
generated shaders.
In order for this to work it is expected that the Docker host exposes
the devices in /dev/dri to the guest system, and that the render nodes
have GID 800 (usually that would be the "render" group, but the GID
for that group is dynamically assigned, so we explicitly agree on a
fixed number).
