Fixes#123. find_program doesn't follow CMP0074 and thus ignores LLVM_ROOT and Clang_ROOT. This change adds LLVM_ROOT and Clang_ROOT to the search path of find_program for llvm-mc and clang in hiprtc to mimics previous add_package behaviour.
Caveat: cmake-specific variables like CMAKE_PREFIX_PATH will take precedence over paths specified with HINTS for find_program, there's no way to change the ordering unless we skip cmake-specific variables all together using NO_CMAKE_PATH and NO_CMAKE_ENVIRONMENT_PATH.
Change-Id: I1fedb60cda09744416e19b3c6e3e0c5c9045f8e7
zichguan-amd
272ef9a7bf