Standard for timezone handling with TZ

[Arthur David Olson]

Attached is my current best effort at dealing with "GMT" files in the time
zone package.  I'd very much welcome any feedback.

				--ado

# @(#)etcetera	7.2

# All of these are set up just so people can "zic -l" to a timezone
# that's right for their area, even if it doesn't have a name or DST rules
# (half hour zones are too much to bother with -- when someone asks!)

Zone	GMT		0	-	GMT
Link	GMT		UTC
Link	GMT		UCT
Link	GMT		Universal
Link	GMT		Greenwich
Link	GMT		Zulu
Link	GMT		GMT-0
Link	GMT		GMT+0
Link	GMT		GMT0

# We use POSIX-style signedness in the names and output,
# internal-style signedness in the specifications.
# These are shoved down into an "Etc" directory so we get a name change--
# in earlier incarnations, we had lines such as
#		Zone	GMT-12		-12	-	GMT-1200
# and do not want things to change quietly if someone accustomed to the old
# way does a
#		zic -l GMT-12

Zone	Etc/GMT-12	12	-	GMT-12
Zone	Etc/GMT-11	11	-	GMT-11
Zone	Etc/GMT-10	10	-	GMT-10
Zone	Etc/GMT-9	9	-	GMT-9
Zone	Etc/GMT-8	8	-	GMT-8
Zone	Etc/GMT-7	7	-	GMT-7
Zone	Etc/GMT-6	6	-	GMT-6
Zone	Etc/GMT-5	5	-	GMT-5
Zone	Etc/GMT-4	4	-	GMT-4
Zone	Etc/GMT-3	3	-	GMT-3
Zone	Etc/GMT-2	2	-	GMT-2
Zone	Etc/GMT-1	1	-	GMT-1
Zone	Etc/GMT+1	-1	-	GMT+1
Zone	Etc/GMT+2	-2	-	GMT+2
Zone	Etc/GMT+3	-3	-	GMT+3
Zone	Etc/GMT+4	-4	-	GMT+4
Zone	Etc/GMT+5	-5	-	GMT+5
Zone	Etc/GMT+6	-6	-	GMT+6
Zone	Etc/GMT+7	-7	-	GMT+7
Zone	Etc/GMT+8	-8	-	GMT+8
Zone	Etc/GMT+9	-9	-	GMT+9
Zone	Etc/GMT+10	-10	-	GMT+10
Zone	Etc/GMT+11	-11	-	GMT+11
Zone	Etc/GMT+12	-12	-	GMT+12
Zone	Etc/GMT+13	-13	-	GMT+13	# GMT offset 12 hours with DST