Getting Verilator working on Mac

[bradjc]

Goal: make verilator support cross platform and work on Mac.

Work in progress: #2975

[lschuermann]

Would getting it to work in Docker (at least the fully CI workflow) qualify as "working on Mac"? I think that could relieve some of the struggles people have with reconstructing CI results even on Linux, but more generally also on Windows and macOS. (Assigning myself for a cross-platform solution e.g. Vagrant or Docker, don't have a Mac).

[ppannuto]

I think for the purposes of the "heavyweight" things, yes. This is more about ensuring a principle that any developer can replicate any CI failure locally; Docker is admittedly non-zero lift, but so is any realistic install of Verilator.