bug#4446: remove ###autoload from ediff-hook.el

[Stefan Monnier]

> The ###autoload in ediff-hook.el is not needed, this file is in the
> dumped image, so the autoload's only effect is to make loaddefs.el
> bigger and increase the size of the dumped image.

> The comment in the file says that the autoload is needed for XEmacs, but
> that's not a good reason to keep it in the Emacs CVS, it's a one line
> change to a file that almost never changes.

> OK to remove the autoload line?

Actually, it reminds me that I faced a similar situation recently.
I did remove the autoload cookie, but in retrospect I think it was the
wrong thing to do.  We should instead teach our build system to skip
preloaded files when creating the loaddefs.el file.


        Stefan