This assumes you have installed the command line tools on macOS. The first two sections look into installing OpenMP from scratch. However, on macOS it might be easier just to use homebrew.
- Download source from https://github.com/Kitware/CMake/releases/download/v3.15.1/cmake-3.15.1.tar.gz (there may be a later release).
- Untar the files:
tar xzvf cmake-3.15.1.tar.gz