You're moving the goal posts. I'm not interested in SDKs that cannot work on a given OS or CPU, I just want to update the compiler to make use of progress in t

You're moving the goal posts. I'm not interested in SDKs that cannot work on a given OS or CPU, I just want to update the compiler to make use of progress in the language, without being forced by Apple to buy new hardware for that, or install a different OS. You pretending these things cannot be separated looks deeply disingenuous.