Backport cxd4 changes.

[Narann]

There has been many changes in the original repo. This ticket is here as a reminded to follow backport effort.

[AmbientMalice]

I notice that the original repo has received a number of improvements recently. Maybe m64p's version should be updated?

[loganmc10]

My preference would actually be to incorporate mupen64plus support into the upstream repo, I'm not sure why that wasn't done originally, but copying over commits can be a tad tedious.

[Narann]

@cxd4 ?

[cxd4]

That's up to you guys to manage. I have no familiarity with Mupen64Plus's revision to the plugin API nor any interest in studying it. Anything you guys can PR that doesn't interfere with the current code paths for the older spec I am pretty much fine with blindly merging.

Try to keep all changes to module.c or the spec header since that handles the subsystem interface with the actual RSP emulator (every other translation unit except module.c).

I recall bobby smiles saying he was able to add some kind of simple switch to toggle when compiling his audio plugin in different modes that quickly set the preprocessor to target zilmar's spec or Mupen64Plus' spec; his plugin probably has some good examples on how to wrap that around here.

[cxd4]

Why wasn't it done originally? Humm...no idea. ecsv was the only person I knew from Mupen64Plus who was working with me about stuff like adjusting the license and other conformity. If memory serves I think he probably asked me right from the beginning upon initial contact how I felt about having M64Plus "API" code in my plugin and I didn't perceive a comfortable feeling from that question. Whatever my answer was, I think he was just being flexible and decided to redo my commits.

[Narann]

Thanks for the info @cxd4 :)