Sync zoneinfo database with tzdata2017c from ftp://ftp.iana.org/tz/releases

Sync zoneinfo database with tzdata2017c from ftp://ftp.iana.org/tz/releases

* Northern Cyprus switches from +03 to +02/+03 on 2017-10-29.

* Fiji ends DST 2018-01-14, not 2018-01-21.

* Namibia switches from +01/+02 to +02 on 2018-04-01.

* Sudan switches from +03 to +02 on 2017-11-01.

* Tonga likely switches from +13/+14 to +13 on 2017-11-05.

* Turks & Caicos switches from -04 to -05/-04 on 2018-11-04.

For a detailed list of changes, see share/zoneinfo/NEWS.