Version dependent code

[Rachael]

That would be really bad, in my opinion. Because what is to stop someone from creating an LZDoom mod that might be compatible with both GZDoom and QZDoom?

LZDoom is kind of the odd-man-out on this one. The accounting can be done either on LZDoom or GZDoom side (i.e. GZDoom just loads a "modern" filter folder), but the separation should be the ports that already exist, not the 26 different letters of the alphabet that happen to get stuck in front of the "ZDoom" name, or probably what might be better if a port just created its own name instead of using "ZDoom" whatsoever.

Things are far more likely to be compatible with GZDoom than with LZDoom, and most ports will derive from GZDoom.