This directory contains an external program, vzic, which generates icalendar
zone information files from the official tzdata files.  In order to update the
iCalendar files used by the datatracker for zone information, run 'make zoneinfo'
in this directory.  This will generate new zoneinfo data by fetching the
latest tzdata file from ietf.org/timezones/tzdata-latest.tar.gz and running
vzic to update the .ics files as needed.