(updated patch set attached)

Hello Prof. Becerra,

Thanks for your response!  I forgot to mention the context of this
message:  I am trying to get PSOPT (and ADOL-C, and ColPack) packaged
for GNU Guix.

Please note that I have updated:
* The homepage URL
* Added gnuplot (not required, but awfully nice :-)

Warm regards,
Eric Brown