- dx10 is deprecated
- dx11 -> dxbc
- use appropriate gl target based on shader type
- add wgsl
- add dxil (dx12)
dxil is a bit of an odd one as bgfx dynamically loads the compiler
runtime from the shaderc binary path, so i've added some extra
configuration to copy the appropriate vendored binaries over to the
build output/install directories.
10a9ed2220