8f59de9d2b
See [the documentation](https://cmake.org/cmake/help/v3.0/command/find_package.html)
for exactly how the search procedure works. If you want to use an
LLVM from a specific location, use CMAKE_PREFIX_PATH as normal.
No longer do we have a nonstandard HIPIFY_CLANG_LLVM_DIR variable
for people to learn about.
[ROCm/clr commit: de8dcf0ed2]