[OS X Emacs] diff -a?

[Rodney Sparapani]

Perhaps this is a Leopard issue.  But, it seems that when file thinks 
that your text files are data, then diff gives an error message like:
Binary files A and B differ

This could be rectified with an alias for the command line.  But, I 
rarely use diff on the command line, mostly via emacs.  So, in .emacs 
you can:
(setq ediff-diff-options "-a")

Oh, and setting this after ediff has been started is too late.  So,
you really need it in your .emacs and it's a tail chaser the first
time you see it.

So, I'm wondering if this should just be the default on OS X.
I see some versions of ediff-diff.el that have a default for MS Windows,
so there is precedent.  However, is this option available on Tiger
(I can't check at the moment)?  In any case, this effects both
Aquamacs and Emacs.app.

By the way, this is not needed here, but how can we easily distinguish
between Aquamacs, Emacs.app, Carbon Emacs, etc.?  Aquamacs conveniently
provides 'aquamacs, but what about the others.  Similarly, all of these 
OS X distros might use uname -r to conveniently provide 'leopard, 
'tiger, etc.  I know: patches welcome.  If we all agree this is a good 
idea, I could do that; I'll just need advice on where these should go.

Thanks,

Rodney