[Agda] agda on emacs 21.4

[Dan Licata]

Hi,

I recently upgraded agda on an old computer, where I only have emacs
21.4 installed. The agda emacs mode no longer works:

- delete-dups, which is called in annotation.el, is not in scope
- no syntax highlighting happens
- loading a file makes the goals appear, but I can't get the point into
  a goal

An older version of the emacs mode (from September) worked on this
version of emacs, and the newer version works fine on my laptop, which
is running a newer version of emacs.  

I'd like to get the newer versions of agda running in this environment,
if possible---does anyone have any suggestions?

Thanks!
-Dan