(tz) Support tzdata2015a

The 2015a release of the tz code and data is available. It reflects the following changes, which were either circulated on the tz mailing list or are relatively minor technical or administrative changes:

  Changes affecting future time stamps

    The Mexican state of Quintana Roo, represented by America/Cancun,
    will shift from Central Time with DST to Eastern Time without DST
    on 2015-02-01 at 02:00. (Thanks to Steffen Thorsen and Gwillim Law.)

    Chile will not change clocks in April or thereafter; its new standard time
    will be its old daylight saving time. This affects America/Santiago,
    Pacific/Easter, and Antarctica/Palmer. (Thanks to Juan Correa.)

    New leap second 2015-06-30 23:59:60 UTC as per IERS Bulletin C 49.
    (Thanks to Tim Parenti.)

  Changes affecting past time stamps

    Iceland observed DST in 1919 and 1921, and its 1939 fallback
    transition was Oct. 29, not Nov. 29. Remove incorrect data from
    Shanks about time in Iceland between 1837 and 1908.

    Some more zones have been turned into links, when they differed
    from existing zones only for older time stamps. As usual,
    these changes affect UTC offsets in pre-1970 time stamps only.
    Their old contents have been moved to the 'backzone' file.
    The affected zones are: Asia/Aden, Asia/Bahrain, Asia/Kuwait,
    and Asia/Muscat.

  Changes affecting code

    tzalloc now scrubs time zone abbreviations compatibly with the way
    that tzset always has, by replacing invalid bytes with '_' and by
    shortening too-long abbreviations.

    tzselect ports to POSIX awk implementations, no longer mishandles
    POSIX TZ settings when GNU awk is used, and reports POSIX TZ
    settings to the user. (Thanks to Stefan Kuhn.)

  Changes affecting build procedure

    'make check' now checks for links to links in the data.
    One such link (for Africa/Asmera) has been fixed.
    (Thanks to Stephen Colebourne for pointing out the problem.)

  Changes affecting commentary

    The leapseconds file commentary now mentions the expiration date.
    (Problem reported by Martin Burnicki.)

    Update Mexican Library of Congress URL.

Here are links to the release files:

  ftp://ftp.iana.org/tz/releases/tzcode2015a.tar.gz
  ftp://ftp.iana.org/tz/releases/tzdata2015a.tar.gz

The files are also available via HTTP as follows:

http://www.iana.org/time-zones/repository/releases/tzcode2015a.tar.gz
http://www.iana.org/time-zones/repository/releases/tzdata2015a.tar.gz