bug#8051: 24.0.50; drag and drop operations on mac os x not using dnd-protocol-alist

[emacs user]

It seems that the drag-and-drop operations under mac do not use the
dnd.el mechanism, in particular dnd-protocol-alist is not used.  as a
result, there is an incompatibility with the operation on other systems.
for example, the new support for attachments using dnd in VM seems not
to work under mac.

In GNU Emacs 24.0.50.2 (x86_64-apple-darwin10.6.0, NS apple-appkit-1038.35)
 of 2011-02-10 on MacBook-Air.local
Windowing system distributor `Apple', version 10.3.1038
configured using `configure  '--with-ns' '--without-x''