[profsnuggles]

If you are trying to check what OS you are running wouldn't system-type be better? (eq system-type 'darwin) You could be running X on multiple different systems. Although I checked the output on netbsd and openbsd, both return berkeley-unix as the system-type... which isn't quite as helpful. At least I know if I'm on gnu/linux vs a BSD I guess. The docstring helpfully lets me know that a value of gnu means I'm running on Hurd. It also recognizes gnu/kfreebsd apparently because you can't throw a rock without hitting one of those.

[eddieh]

But I sometimes run X on Mac and I find it helpful to change a few things for Emacs compiled for X vs Emacs.app