Improvements to macOS installer

• Fixes #1893 (closed)
• Fixes #1790 (closed)
• Closes #1894 (closed)
• Fallback to clang requires update of preprocessor
• Check compatibility with meson rewrite of build system
• M2 Mini Runner: MATLAB R2023b arm64 version needs to be installed in /Applications/MATLAB/arm64/R2023b
• M2 Mini Runner: MATLAB R2023b x86_64 version needs to be installed in /Applications/MATLAB/x86_64/R2023b
• M2 Mini Runner: MATLAB R2016b x86_64 version needs to be installed in /Applications/MATLAB/x86_64/R2016b
• Testing on clean installs
• Decide whether to also distribute the package additionally as a zip file
• Fixing the gitlab-ci.yml