Probably there's a very good reason why the devs labeled the mapper buttons mod1, mod2, mod3, instead of Ctrl, Alt, Opt, Cmd, Win, Meta, etc. But in case there isn't a reason, here's a patch that labels the buttons in a user-friendly way, with different labels used for WIN32, MACOSX, and anything else. It might make things easier for beginners, but maybe it messes things up in ways I don't understand - and if it does mess things up, I know the devs will be in their rights to delete it.

It's based on current SVN.

EDIT: After reading ripsaw8080's reply below, I've removed the patch. If anyone wants it for use on a system where you won't change the mod1, etc., mappings, and you're sure it won't cause more problems than it's worth, please PM me.