Move McMurdo and South Pole to 'backward'.

This continues in the series of moving entries to 'backward' if
they exist only because of obsolete tz rules about country codes.
This change does not affect any time stamps after 1970.  Unlike
the previous change in this series, this one does affect time
stamps before 1970, but that's OK as pre-1970 time stamps are
out of scope for the tz database.
* antarctica (Antarctica/McMurdo, Antarctica/South_Pole):
Move to 'backward' and link to Pacific/Auckland.
* backward: Move links here from 'antarctica'.
* zone.tab: Coalesce McMurdo and South Pole, and add Scott Base
to the description.

antarctica

@@ -228,7 +228,8 @@ Zone Antarctica/Syowa	0	-	zzz	1957 Jan 29
 # Scott Island (never inhabited)
 #
 # year-round base
-# Scott, Ross Island, since 1957-01, is like Antarctica/McMurdo.
+# Scott Base, Ross Island, since 1957-01.
+# See Pacific/Auckland.
 #
 # These rules for New Zealand are stolen from the `australasia' file.
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
@@ -337,16 +338,11 @@ Zone Antarctica/Palmer	0	-	zzz	1965
 			-4:00	ChileAQ	CL%sT
 #
 #
-# McMurdo, Ross Island, since 1955-12
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
-Zone Antarctica/McMurdo	0	-	zzz	1956
-			12:00	NZAQ	NZ%sT
+# McMurdo Station, Ross Island, since 1955-12
+# See Pacific/Auckland.
 #
-# Amundsen-Scott, South Pole, continuously occupied since 1956-11-20
-#
-# From Paul Eggert (1996-09-03):
-# Normally it wouldn't have a separate entry, since it's like the
-# larger Antarctica/McMurdo since 1970, but it's too famous to omit.
+# Amundsen-Scott South Pole Station, continuously occupied since 1956-11-20
+# See Pacific/Auckland.
 #
 # From Chris Carrier (1996-06-27):
 # Siple, the first commander of the South Pole station,
@@ -367,5 +363,3 @@ Zone Antarctica/McMurdo	0	-	zzz	1956
 # makes all of the clocks run fast.  So every couple of days,
 # we have to go around and set them back 5 minutes or so.
 # Maybe if we let them run fast all of the time, we'd get to leave here sooner!!
-#
-Link	Antarctica/McMurdo	Antarctica/South_Pole

backward

@@ -27,6 +27,8 @@ Link	America/Rio_Branco	America/Porto_Acre
 Link	America/Argentina/Cordoba	America/Rosario
 Link	America/Guadeloupe	America/St_Barthelemy
 Link	America/St_Thomas	America/Virgin
+Link	Pacific/Auckland	Antarctica/McMurdo
+Link	Pacific/Auckland	Antarctica/South_Pole
 Link	Europe/Oslo		Arctic/Longyearbyen
 Link	Asia/Ashgabat		Asia/Ashkhabad
 Link	Asia/Kolkata		Asia/Calcutta

zone.tab

@@ -45,8 +45,7 @@ AI	+1812-06304	America/Anguilla
 AL	+4120+01950	Europe/Tirane
 AM	+4011+04430	Asia/Yerevan
 AO	-0848+01314	Africa/Luanda
-AQ	-7750+16636	Antarctica/McMurdo	McMurdo Station, Ross Island
-AQ	-9000+00000	Antarctica/South_Pole	Amundsen-Scott Station, South Pole
+AQ	-7750+16636	Pacific/Auckland	McMurdo, South Pole, Scott (New Zealand time)
 AQ	-6734-06808	Antarctica/Rothera	Rothera Station, Adelaide Island
 AQ	-6448-06406	Antarctica/Palmer	Palmer Station, Anvers Island
 AQ	-6736+06253	Antarctica/Mawson	Mawson Station, Holme Bay