Fix debugging on macOS: update or replace llvm-mi with something working

[H-G-Hristov]

The current release of llvm-mi is broken on macOS, which results in basically useless debugging on that platform. I had to switch to CodeLLVM for that reason. Are there any plans to fix, update llvm-mi or somehow make debugging work on that platform out-of-the-box again?
It's not even clear to me who is maintaining that project: https://github.com/lldb-tools/lldb-mi