[clang] Allow installation of Clang .cfg files if they where generated. (PR #105580)

[Vladimir Vereschaka via cfe-commits]

vvereschaka wrote:

There is an example how the clang configuration file can be generated within the cmake cache file during the build configuration
https://github.com/llvm/llvm-project/blob/911e246fe8fd35bd82fc11db001513a1e2f6990c/clang/cmake/caches/CrossWinToARMLinux.cmake#L92

https://github.com/llvm/llvm-project/pull/105580