Also adds OpenMP support for macOS (requires Xcode 7.0, CMake 3.12 and separate libomp from MacPorts/Homebrew)

If you have access to the old closed source waLBerla repository, you may restore the complete history with the following command
git fetch git@i10git.cs.fau.de:software/walberla.git 'refs/replace/*:refs/replace/*'