Updating contrib/prepinfo.awk

[Arnold Robbins]

Hi.

I'd like to update contrib/prepinfo.awk with the current version, if
that's ok. (It's only been, like, 19 years... :-).  The latest version
is a literate program, now available at 
https://github.com/arnoldrobbins/prepinfo.

I would just update the .awk file. I think I still have commit access
to the SVN repo, so I'll just do it directly, but I wanted to let
the maintainers know this is coming.

If it's not OK, please let me know.

Thanks!

Arnold