Hmm, maybe that’s easier indeed. If you really want to complicate making it easy, find the date in CVS in which egldisplay was created, and diff it to glxdisplay at that point, duplicate the current version of glxdisplay and use the diff to replace the GLX stuff with EGL stuff.
Of course, that’s only step one - step two would be to let it inherit from the windisplay code in the case of Windows.
I could help and separate out the code to make it easier for you, but I’m kind of swamped this weekend, so that would have to wait a few days.