CMake Warning (dev) at cmake/FindClang.cmake:46 (find_package):
  Policy CMP0074 is not set: find_package uses <PackageName>_ROOT variables.
  Run "cmake --help-policy CMP0074" for policy details.  Use the cmake_policy
  command to set the policy and suppress this warning.

  CMake variable LLVM_ROOT is set to:

    /d2/llvm/9/vanilla/installs/Release

  For compatibility, CMake is ignoring the variable.
Call Stack (most recent call first):
  CMakeLists.txt:26 (find_package)
This warning is for project developers.  Use -Wno-dev to suppress it.