[Description from CPAN]
diff() provides a basic set of services akin to the GNU diff
utility. It is not anywhere near as feature complete as GNU diff, but it
is
better integrated with Perl and available on all platforms. It is often
faster than shelling out to a system's diff executable for small files,
and generally slower on larger files.

* Add ${CPAN_MIRROR} since default has become flaky

Signed-off-by: Tim Orling <TicoTimo@gmail.com>