And yet it would still work out for Linux if musl, glibc, et al just adopted `API_VERSION_MIN` and `API_VERSION_MAX` macros themselves, it doesn’t actually have

And yet it would still work out for Linux if musl, glibc, et al just adopted `API_VERSION_MIN` and `API_VERSION_MAX` macros themselves, it doesn’t actually have to be handled entirely at the `-isysroot` level.