[ESS] Issue with error/warning messages in Emacs.app

[Stephen Eglen]

To follow up on the mac issue:

> - As I understand it, Carbon is an older technology than Cocoa (on
> which Aquamacs and Emacs.app are based).

Indeed, cocoa is newer; further, the Emacs developers dropped carbon
support a while ago, the 'nextstep' port is the way forward, and this is
in cocoa.

Aquamacs has been great in getting more people using emacs on macs, but
my experience of it has been that it is really suited for those people
who want emacs to behave like any other mac application.  This is fine
for people who mostly work on macs, but this means changing quite a few
defualt Emacs behaviours/keybindings.

Stephen