http://mm.icann.org/pipermail/tz-announce/2015-March/000029.html

- timezone update 2015b
- Changes to time zones:
  * Mongolia DST observance 2015
  * Palestine DST dates 2015 and 2015
  * correct 1982 zone shift in Pacific/Easter, regression in 2015a

  * More pre-1970 zones have been turned into links, when they differed
    from existing zones only for older time stamps:
    America/Antigua, America/Cayman, Pacific/Midway, and Pacific/Saipan.
  * Correct the 1992-2010 DST abbreviation in Volgograd from "MSK" to "MSD".
- Changes to code:
  * Fix integer overflow bug in reference 'mktime' implementation.
  * Allow -Dtime_tz=time_t compilations, and allow -Dtime_tz=... libraries
    to be used in the same executable as standard-library time_t functions.