There's a very well-known utility by the name of "patch" written by
Larry Wall. It can process the "diff -c" style patches thet Lance
posted, as well as most other diff formats produced by various
variants of UNIX diff (I don't expect it will handle non-UNIX diff
formats unless these were designed to be compatible with UNIX diff).
Patch is available from many ftp sites and even distributed with some
OS versions. I'm pretty sure that all the ftp sites carrying Python
(with the exception of ftp.cwi.nl) carry a version of patch.
--Guido van Rossum, CWI, Amsterdam <Guido.van.Rossum@cwi.nl>