* Updated to use the latest swig and llvm 15.
* Updated to use the latest llvm that comes with the macos docker image.
* Added missing install
* Test without installing llvm
* Tested to link llvm
* Changed back to use downloaded llvm+clang package.
* Check if macos (13-arm) image can find the installed udunits.
* Try macos-13 if it works as documented
* Need to match the cpu type of macos and the build for clang+llvm.
* Change to Mac-12 for gtest.h to be found.
* Switch back to Mac-13 as gtest.h is not a factor for this CI process..
* Updated to use SWIG 4.1.1 due to SWIG 2.0 generats setter wrapper for private constructor or operator.
* Needed to go to unzipped swig-4.1.1 directory before building it.
* Install needed packages for being able to run SWIG 4.1.1 build script.
