Update to tzdata version 2018f.

https://mm.icann.org/pipermail/tz-announce/2018-October/000051.html

data/CONTRIBUTING

@@ -17,11 +17,14 @@ To email small changes, please run a POSIX shell command like
 'diff -u old/europe new/europe >myfix.patch', and attach
 myfix.patch to the email.
 
-For more-elaborate changes, please read the theory.html file and browse
-the mailing list archives <https://mm.icann.org/pipermail/tz/> for
-examples of patches that tend to work well.  Additions to
-data should contain commentary citing reliable sources as
-justification.  Citations should use https: URLs if available.
+For more-elaborate or possibly-controversial changes,
+such as renaming, adding or removing zones, please read
+<https://www.iana.org/time-zones/repository/theory.html> or the file
+theory.html.  It is also good to browse the mailing list archives
+<https://mm.icann.org/pipermail/tz/> for examples of patches that tend
+to work well.  Additions to data should contain commentary citing
+reliable sources as justification.  Citations should use https: URLs
+if available.
 
 Please submit changes against either the latest release in
 <https://www.iana.org/time-zones> or the master branch of the development

data/README

@@ -4,7 +4,7 @@ README for the tz distribution
 "Any time you want it to be." -- Frank Baxter as The Scientist
 					(from the Bell System film "About Time")
 
-The Time Zone Database (often called tz or zoneinfo) contains code and
+The Time Zone Database (called tz, tzdb or zoneinfo) contains code and
 data that represent the history of local time for many representative
 locations around the globe.  It is updated periodically to reflect
 changes made by political bodies to time zone boundaries, UTC offsets,
@@ -20,17 +20,15 @@ substituting your desired installation directory for "$HOME/tzdir":
 	make TOPDIR=$HOME/tzdir install
 	$HOME/tzdir/usr/bin/zdump -v America/Los_Angeles
 
-Historical local time information has been included here to:
+This database of historical local time information has several goals:
 
-*	provide a compendium of data about the history of civil time
-	that is useful even if not 100% accurate;
+ * Provide a compendium of data about the history of civil time that
+   is useful even if not 100% accurate.
 
-*	give an idea of the variety of local time rules that have
-	existed in the past and thus an idea of the variety that may be
-	expected in the future;
+ * Give an idea of the variety of local time rules that have existed
+   in the past and thus may be expected in the future.
 
-*	provide a test of the generality of the local time rule description
-	system.
+ * Test the generality of the local time rule description system.
 
 The information in the time zone data files is by no means authoritative;
 fixes and enhancements are welcome.  Please see the file CONTRIBUTING

data/SOURCE

@@ -1,2 +1,2 @@
 The files in this directory were obtained from the IANA Time Zone Database
-http://www.iana.org/time-zones, version 2018e.
+http://www.iana.org/time-zones, version 2018f.

data/africa

@@ -1,3 +1,5 @@
+# tzdb data for Africa and environs
+
 # This file is in the public domain, so clarified as of
 # 2009-05-17 by Arthur David Olson.
 
@@ -6,7 +8,7 @@
 # [email protected] for general use in the future).  For more, please see
 # the file CONTRIBUTING in the tz distribution.
 
-# From Paul Eggert (2017-04-09):
+# From Paul Eggert (2018-05-27):
 #
 # Unless otherwise specified, the source for data through 1990 is:
 # Thomas G. Shanks and Rique Pottenger, The International Atlas (6th edition),
@@ -51,13 +53,15 @@
 # I vaguely recall 'WAT' also being used for -01 in the past but
 # cannot now come up with solid citations.
 #
-# I invented the following abbreviations; corrections are welcome!
-#	 +02	WAST	West Africa Summer Time (no longer used)
-#	 +03	CAST	Central Africa Summer Time (no longer used)
-#	 +03	SAST	South Africa Summer Time (no longer used)
+# I invented the following abbreviations in the 1990s:
+#	 +02	WAST	West Africa Summer Time
+#	 +03	CAST	Central Africa Summer Time
+#	 +03	SAST	South Africa Summer Time
 #	 +03	EAT	East Africa Time
-# 'EAT' also seems to have caught on; the others are rare but are paired
-# with better-attested non-DST abbreviations.
+# 'EAT' seems to have caught on and is in current timestamps, and though
+# the other abbreviations are rarer and are only in past timestamps,
+# they are paired with better-attested non-DST abbreviations.
+# Corrections are welcome.
 
 # Algeria
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
@@ -362,6 +366,13 @@ Zone	Africa/Cairo	2:05:09 -	LMT	1900 Oct
 # Eritrea
 # Ethiopia
 # See Africa/Nairobi.
+#
+# Unfortunately tzdb records only Western clock time in use in Ethiopia,
+# as the tzdb format is not up to properly recording a common Ethiopian
+# timekeeping practice that is based on solar time.  See:
+# Mortada D. If you have a meeting in Ethiopia, you'd better double
+# check the time. PRI's The World. 2015-01-30 15:15 -05.
+# https://www.pri.org/stories/2015-01-30/if-you-have-meeting-ethiopia-you-better-double-check-time
 
 # Gabon
 # See Africa/Lagos.

data/antarctica

@@ -1,3 +1,5 @@
+# tzdb data for Antarctica and environs
+
 # This file is in the public domain, so clarified as of
 # 2009-05-17 by Arthur David Olson.