Not really easy in any regard. Old versions that still have netplay code require very old compilers and libs to build.
Newer versions don't have netplay, so you'd have to handle everything (plus it would still desync). They don't build easily either due to so many changes in the various libs used. -_-
Yeah, thinking of the libs, it may not be something feasible to achieve. I may look the old source code to see what can be done.
Well, if any of these programs can be set up for a networked game from the command line, You could probably have some sort of generic lobby system with configurable programs, or even make specific programs for them externally that handles lobbies and chat, and when yous go to play, it can just have the one person host and another connect. Would be nice if it was built in to the emulators, but if it's impractical or impossible or just not likely due to project priorities, an external utility isn't an awful compromise.
That's what I was thinking. Something easy that may help people to find other players w/o any external piece of software. An IRC chat would be nice though.
You should look at RetroArch, that's a multi-system emulator available for multiple operating systems and platforms, and it also has a decent stab at netplay. Now if only someone could contribute a chat system to it. Maybe something based off an IRC server, perhaps.
Thank you... I didn't know about RetroArch existence. I'll give it a try!