Unfortuantely different versions of DXC accept or fail differently
in some cases. We don't care too much about validating the DXC
behavior itself, but it's useful that all the CI jobs use the
same version so that we don't have to complicate the shader runner
language.
The macOS version is currently bound to be pretty recent because
otherwise libdxil.dylib is not provided. So I'm updating the
Linux and Windows version as well.
I don't expect it should be particularly hard for other maintainers
to keep up with the DXC updates, since it just amounts to
downloading a ZIP file and extracting two libraries.
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).
