Investigate fmopl module licensing

[dcoshea]

wraithverge* reported via email:

the license of "fmopl.c" is questionable. They've changed it from MAME to GPL a few years ago, but aside from the C++ modifications in the official "fmopl.cpp", it's the same code-base.

Jarek's editions were originally MAME licensed, however, as I'd alluded to before, it now appears to be technically dual-licensed. I suppose the real question is, does the GPL override the MAME license in "fmopl.c" ? (I think it does ...)

DarkOne used Satoh's original version, which is only GPLv2

maybe it would be less headache to just use "dbopl.cpp" from DOSBox -- I've already ported it into my AdPlug-based "OPLx Amp" plugin over a year ago, and it does have a discrete OPL2 mode -- It's touted as being 'fast' at the expense of some inaccuracy, which may be a reasonable compromise for people in your situation.

The fmopl.[ch] files don't indicate what license applies to them. Some investigation is required to determine whether they are being redistributed validly as part of this project (and were redistributed validly as part of NewWolf).