Hi,

Whilst working on the Reproducible Builds effort [0], we noticed that
ruby-gnuplot could not be built reproducibly.

This is because it ships a different binary package depending on
whether the testsuite is run or not. Specifically, sin_wave.gif is
generated in the tests only (not in the build); a patch is attached
that will delete this file and ensure it is not shipped in the
binary package.

 [0] https://reproducible-builds.org/


Regards,