Hello bearophile,
But it's economically advantageous for Microsoft to make it easy for people to create new compilers and languages for Windows that work well with other Windows programs. So in my opinion having a good Clang++ on Windows is good for the economic well-being of Windows. They can grant LLVM a free licence to use Windows-style exceptions.
It should be safe to assume that most windows programs (by how many are running) are compiler with MSVC and at $800 to $5000 (and up IIRC) a pop why should they do anything to help the competition? Seriously, I suspect that GCC, LLVM, etc. are literally irrelevant to how much MS makes off Windows.
-- ... <IXOYE><
