Updating package for p5 module Date::Calc from 5.4nb3 to 5.6

pkgsrc changes:
  - Adding license (perl5 license, according to module's doc)
  - Adjust dependencies according to META.yml
  - Removing obsoleted deletion of formerly included Carp::Clan

Upstream changes:
Version 5.6  28.07.2009

+  Made the module MacOS X compatible
+  Made some tiny changes to the documentation

Version 5.5  was skipped due to an unauthorized upload by someone else

(sno)