Skip DXC dependency if BUILD_SHADERS isn't defined
Skip DXC dependency if BUILD_SHADERS isn't defined

Thanks @olegat!
Before, DXC was needed to get through the CMake process, even if the user doesn't intend to rebuild the shaders. We don't do that anymore.

Plus fix bad EOLs in CMakeLists.txt
googlestadia/PorQue4K,googlestadia/PorQue4K,googlestadia/PorQue4K