I'm pretty sure the problems I'm having are from the "unix" side of setting things up, but it also seems likely to me that a lot more people who own Windows machines might have experience solving this problem, so I'm posting a link to it here too:
Any tips on properly installing OpenGL in cygwin would help. The web is replete with advice, the problem is, it's a mish-mash of the last two decades and a lot of it is now not applicable to current versions, leads to dead links, or applies to proprietary hardware not being made anymore, etc etc etc.. there's a myriad of confusing info out there, and all I can really say for sure is that the default installer didn't get the job done.