This Perl 5 script can be used to port a diff to a newer version of the original software.
Example 1: port a kernel patch to linux-2.4.17
diffport some.diff linux-2.4.17.tar.gz
Example 2: port two patches to XFree86 4.0.3
diffport first.diff second.diff -p 4.0.2-4.0.3.diff.gz X402src-1.tgz X402src-2.tgz X402src-3.tgz