Building with cmake 3.16, I get the following warning:
CMake Warning (dev) at /usr/share/cmake-3.16/Modules/CheckIncludeFiles.cmake:120 (message): Policy CMP0075 is not set: Include file check macros honor CMAKE_REQUIRED_LIBRARIES. Run "cmake --help-policy CMP0075" for policy details. Use the cmake_policy command to set the policy and suppress this warning. CMAKE_REQUIRED_LIBRARIES is set to: m For compatibility with CMake 3.11 and below this check is ignoring it. Call Stack (most recent call first): /home/jprotze/OMPD/llvm-project/openmp/runtime/cmake/config-ix.cmake:223 (check_include_files) /home/jprotze/OMPD/llvm-project/openmp/runtime/CMakeLists.txt:223 (include) This warning is for project developers. Use -Wno-dev to suppress it.
The cmake_minimum_required command in the OpenMP directory overwrites the policy setting of llvm. Also, we want to support stand-alone builds, so we should set the policy.
lldb introduced the same patch in : https://reviews.llvm.org/D58279