[OS X Emacs] Tab completion for .mailrc, and Xcode external editor

[John Velman]

Wow.  That was a test all right.  A test of how different Mutt+.mail_alias is from Gnus + .mailrc.

I got every word in the quoted "Emacs on Mac OS X Mailing List" +cox.net as a CC. address.  I've got a bigger problem than alias tab completion!

I haven't used vanila mail + .mailrc since about 1986.  Well, my mailrc isn't very long.  I can fix this with some editing.

Best

John Velman