Quality of this commit is questionable. I have no idea whether what I did
here makes sense or not.
But it compiles and runs (provided with hlsdk-xash3d amd64 build, which
is another story).
This omits necessary waf changes that are necessary to make a valid
64-bit build. Apparently it's not enough to just pass `-8` on Windows,
you also need to hack wscript to add `x64` target to MSVC. I'll do that
later when I figure out how.
This change is a precursor for RTX Vulkan effort --
VK_KHR_ray_tracing_pipeline and friends are only available on 64-bit
nvidia drivers (no idea about AMD, pls send GPUs onegai).