OpenMP support on MAC

[wpotrzebowski]

During code camp XI @wpotrzebowski played with enabling OpenMP calculations for sasmodels. While the benchmark was quite crude it seemed to provide speed at the order 5x.

In order to enable it I had to install required libraries
curl - O https://mac.r-project.org/openmp/openmp-14.0.6-darwin20-Release.tar.gz
sudo tar fvxz openmp-14.0.6-darwin20-Release.tar.gz - C /

and make some changes to sasmodels https://github.com/SasView/sasmodels/compare/macos_openmp

[wpotrzebowski]

openmp libraries are from llvm project and have license that should allow using it https://github.com/llvm/llvm-project/blob/main/LICENSE.TXT in SasView

[wpotrzebowski]

I am thinking if this is way forward for MAC (given OpenCL) doesn't really work anymore?