Here's what I have staged for commit. A few notes:
* I moved the new function to option_utils.c and added a macro that takes
care of figuring out the number of arguments.
* I removed the derivative flags. I know I lobbied for those, but they
seemed out of place for this patch. Maybe we can add them separately.
* I limited the number of new tests to one per call to
check_mut_excl_opts(). I didn't see much benefit from testing everything
exhaustively.
--
nathan
