Proof of concept version of a calendar port

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Summary

This port builds the calendar program from FreeBSD-CURRENT as a port

It is meant to provide RELEASE versions with a calendar program that works with data from the calendar-data port.

For this purpose it depends on the misc/calendar-data port (to be moved to deskutils/calendar-data before this port is committed).

Test Plan

Build with and without NLS option

Install and test with calendar data files in /usr/share/calendar and /usr/local/share/calendar