I've been rewriting GBHawk as a C++ core so that all my cores have the same architecture. I've managed to get linking working in a much more compact way in the new core. I'll take what I learned in this process to redo the GBA linking for 4 players eventually.
I've also moved my NES core here as experimental so that everything is in the same place, no point having things spread out to multiple projects.
I've also added blank cores for SNES and N64. No clue when I might actually develop them, but I've found that when I'm too tired to do core development I can still make progress on the infrastructure stuff that doesn't take a lot of brain power largely copy paste from the other cores.
I've also removed a LOT of stuff from the front end code as I try to shrink and simplify it. Eventually I will move to the same lua structure as current BizHawk which will be another simplification.
Now that the GBHawk rewrite is done I can get back to GBA linking improvements and work on a new release.
I fixed RTC emulation and now pass all of the tests by CasualPokePlayer. I think a lot of things are still wrong, but this now runs a lot closer to how the actual chip works so is improvable in the future if more tests are made.