> buffer-undo-list is initially nil regardless of how I open the file.
 > When I open the file from the command line and then press C-M-x on the
 > first form, `buffer-undo-list' is with CVS trunk:
 >
 >    (nil
 >     (96 . 106)
 >     (t 18643 . 10108))
 >
 > whereas with Emacs 22.2, it is:
 >
 >    (nil
 >     (96 . 106)
 >     1
 >     (t 18643 . 10108))

Hmmm...  Can you try the attached patch?

martin