@Passion3D I see your point about being disappointed on not having VisualStudio for Mac supporting C++ but it's the status-quo and we can't do anything to change it.
With regard to the link you've pointed it actually refers to Visual Studio Code which is indeed a different product compared to Visual Studio for Mac and Visual Studio.
@janbiko even modifying the CMakeList.txt file in order to support Apple platform at the compile time, C4DImporter.cpp refuses to compile because it has been designed only to be compiled under MSVC. And this is another reason to check with AssImp community for bringing the required changes.
Last but not least AssImp looks to support only Melange 16.x.x which is five revisions older than the current one. It could happen in the end that due to the changes that Melange has undergone in the course of these years compatibility might break up.