cad/calculix-ccx: Update to version 2.15.
- Update to the latest version. Changelog: http://www.dhondt.de/new_calc.htm
- Attempt to make the build reproducible concerning the date in the executable.
- Drop temporarily) the taucs dependency. It brings a secondary dependency on metis4 which we are not packaging. We will bring taucs back when it depends on metis5
- Pet portlint.
Approved by: thierry (mentor)