Add PKST to the default set of timezone abbreviations.

Per discussion, if we have PKT in there then PKST should be too.
Also, fix mistaken claim that these abbrevs are not known to zic.

src/timezone/tznames/Asia.txt

@@ -4,7 +4,7 @@
 #   a template for timezones you could need.  See the `Date/Time Support'
 #   appendix in the PostgreSQL documentation for more information.
 #
-# $PostgreSQL: pgsql/src/timezone/tznames/Asia.txt,v 1.3.4.1 2009/09/06 15:25:31 tgl Exp $
+# $PostgreSQL: pgsql/src/timezone/tznames/Asia.txt,v 1.3.4.2 2010/05/11 22:36:58 tgl Exp $
 #
 
 # CONFLICT! ADT is not unique
@@ -201,7 +201,10 @@ PETST   46800 D  # Petropavlovsk-Kamchatski Summer Time
 PETT    43200    # Petropavlovsk-Kamchatski Time
                  #     (Asia/Kamchatka)
 PHT     28800    # Phillipine Time (not in zic)
-PKT     18000    # Pakistan Time (not in zic)
+PKT     18000    # Pakistan Time
+                 #     (Asia/Karachi)
+PKST    21600 D  # Pakistan Summer Time
+                 #     (Asia/Karachi)
 QYZT    21600    # Kizilorda Time
                  #     (Asia/Qyzylorda)
 SAKST   39600 D  # Sakhalin Summer Time

src/timezone/tznames/Default

@@ -4,7 +4,7 @@
 # timezone_abbreviations to 'Default'.  See the `Date/Time Support'
 # appendix in the PostgreSQL documentation for more information.
 #
-# $PostgreSQL: pgsql/src/timezone/tznames/Default,v 1.7.2.1 2009/09/06 15:25:31 tgl Exp $
+# $PostgreSQL: pgsql/src/timezone/tznames/Default,v 1.7.2.2 2010/05/11 22:36:58 tgl Exp $
 
 
 #################### AFRICA ####################
@@ -334,7 +334,10 @@ PETST   46800 D  # Petropavlovsk-Kamchatski Summer Time
 PETT    43200    # Petropavlovsk-Kamchatski Time
                  #     (Asia/Kamchatka)
 PHT     28800    # Phillipine Time (not in zic)
-PKT     18000    # Pakistan Time (not in zic)
+PKT     18000    # Pakistan Time
+                 #     (Asia/Karachi)
+PKST    21600 D  # Pakistan Summer Time
+                 #     (Asia/Karachi)
 SGT     28800    # Singapore Time
                  #     (Asia/Singapore)
 TJT     18000    # Tajikistan Time