Change prefix for musl targets to not use wrapper

[Timmmm]

This should fix cross-compilation to musl when you haven't manually set the compiler name. It's also more consistent with the existing musl targets (e.g. mips).

See #105 and https://github.com/FiloSottile/homebrew-musl-cross#:~:text=If%20you%20encounter%20issues

Tested with brew install FiloSottile/musl-cross/musl-cross on Mac.

[Timmmm]

Uhm not sure why the tests are failing and there's no error messages :-/

[m-ou-se]

At least on Arch Linux, the musl package for x86-64 contains musl-gcc, but not x86_64-linux-musl-cc.

[Timmmm]

Yeah I figured that out eventually. IIRC it's the same on Debian based distros too unfortunately.

I guess searching for both options might be an option, or using x86_64-linux-musl-cc on all host platforms except Linux.