[Experiment]: bundled with dxc (as a feature?)

[CrazyboyQCD]

https://github.com/hexops/mach-dxcompiler (CC-BY-4.0) :
features(copied):

• Statically linked dxcompiler library and dxc executables.
• Zero dependency on proprietary dxil.dll code-signing blob (see: Mach Siegbert Vogt DXCSA)
• Built using build.zig instead of 10k+ LOC CMake build system.
• Simple C API bundled into library as an alternative to the traditional COM API.

[Wumpf]

given that mach-dxcompiler is very experimental itself that would be doubly so in wgpu.
But behind a feature flag why not, imho worth a shot if someone wants to pick it up and see how maintainable that would be.

Still rooting though for SpirV in DX12 becoming a thing asap 😄