Adding new function (new debug targets) - pointers?

[papadeltasierra]

Refs: https://github.com/dholth/blackmagic and https://community.silabs.com/s/question/0D51M00007xeM64SAE/adding-support-for-efr32-to-the-black-magic-probe?language=en_US
I'm trying to use Black Magic Probe with an EFM32 and I can get as far as using monitor swdp_scan to detect the AAP port but then att 1 just hangs. I suspect I need the changes that dholth has created but my attempts to use them have not succeeded. I have a suspicion I'm simply using the wrong pins (monitor swdp_scan doesn't even detect the port) but I know that the very latest Black Magic Probe code at least uses the pins I expect so I am considering forking and forward-applying dholth's changes to the latest Black Magic Probe code.
I note that there is some issue about merging the flashing code which makes me wonder if I need a new build flag, maybe something like TARGET=EFM32 and build a special build. Would that be the preferred way to go or is there a better way?
Ideally I would like the code to be acceptable to be part of the official Black Magic Probe codebase, if I can make that work.
Thanks for your suggestions/ideas/guidance.