The source code for the OpenGL version wasn't taken down, because it technically doesn't have any Nintendo assets or code (which is why they haven't DMCAed it). It requires a (not included) .Z64 ROM of the US or JP version of the game, and must be compiled (more info on that), but I'm not sure what our stance is.
Topic on Talk:Super Mario 64
Based on what you said, I don't see a problem linking it. It doesn't seem any different than linking to a Nintendo 64 emulator, since people who legally own Super Mario 64 should be able to play it.