diff --git a/winsup/cygwin/release/1.7.10 b/winsup/cygwin/release/1.7.10
index 6ab2d579e..2a52ef03a 100644
--- a/winsup/cygwin/release/1.7.10
+++ b/winsup/cygwin/release/1.7.10
@@ -4,6 +4,9 @@ What's new:
 - New getconf tool for querying confstr(3), pathconf(3), sysconf(3), and
   limits.h configuration.
 
+- New tzset utility to generate a POSIX-compatible TZ environment
+  variable from the Windows timezone settings.
+
 - The passwd tool now allows an administrator to use the -R command for
   other user accounts:  passwd -R username.
 
diff --git a/winsup/doc/ChangeLog b/winsup/doc/ChangeLog
index 8733fc912..790b6e979 100644
--- a/winsup/doc/ChangeLog
+++ b/winsup/doc/ChangeLog
@@ -1,3 +1,7 @@
+2012-01-29  Corinna Vinschen  <corinna@vinschen.de>
+
+	* new-features.sgml (ov-new1.7.10): Add tzset.
+
 2012-01-24  Corinna Vinschen  <corinna@vinschen.de>
 
 	* pathnames.sgml (mount-table): Rephrase a few expressions for
diff --git a/winsup/doc/new-features.sgml b/winsup/doc/new-features.sgml
index 57f5192a1..eea88174a 100644
--- a/winsup/doc/new-features.sgml
+++ b/winsup/doc/new-features.sgml
@@ -38,6 +38,11 @@ New <command>getconf</command> command for querying confstr(3), pathconf(3),
 sysconf(3), and limits.h configuration.
 </para></listitem>
 
+<listitem><para>
+New <command>tzset</command> utility to generate a POSIX-compatible TZ
+environment variable from the Windows timezone settings.
+</para></listitem>
+
 <listitem><para>
 The passwd command now allows an administrator to use the -R command for
 other user accounts:  passwd -R username.
diff --git a/winsup/utils/ChangeLog b/winsup/utils/ChangeLog
index 858d6bc18..f13b95382 100644
--- a/winsup/utils/ChangeLog
+++ b/winsup/utils/ChangeLog
@@ -1,3 +1,9 @@
+2012-01-29  Corinna Vinschen  <corinna@vinschen.de>
+
+	* Makefile.in (CYGWIN_BINS): Add tzset.
+	* tzset.c: New tool, new file.
+	* utils.sgml (tzset): New section.
+
 2012-01-24  Yaakov Selkowitz  <yselkowitz@users.sourceforge.net>
 
 	* ldd.cc (start_process): Handle .oct and .so as DLLs.
diff --git a/winsup/utils/Makefile.in b/winsup/utils/Makefile.in
index bea7070c6..f85dd84ed 100644
--- a/winsup/utils/Makefile.in
+++ b/winsup/utils/Makefile.in
@@ -53,7 +53,7 @@ MINGW_CXX        := ${srcdir}/mingw ${CXX} -I${updir}
 # List all binaries to be linked in Cygwin mode.  Each binary on this list
 # must have a corresponding .o of the same name.
 CYGWIN_BINS := ${addsuffix .exe,cygpath getconf getfacl ldd locale kill mkgroup \
-        mkpasswd mount passwd ps regtool setfacl setmetamode ssp umount}
+        mkpasswd mount passwd ps regtool setfacl setmetamode ssp tzset umount}
 
 # List all binaries to be linked in MinGW mode.  Each binary on this list
 # must have a corresponding .o of the same name.
diff --git a/winsup/utils/tzset.c b/winsup/utils/tzset.c
new file mode 100644
index 000000000..568dc47b2
--- /dev/null
+++ b/winsup/utils/tzset.c
@@ -0,0 +1,718 @@
+/* tzset.c: Convert current Windows timezone to POSIX timezone information.
+
+   Copyright 2012 Red Hat, Inc.
+
+This file is part of Cygwin.
+
+This software is a copyrighted work licensed under the terms of the
+Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
+details. */
+
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <getopt.h>
+#include <cygwin/version.h>
+#include <windows.h>
+
+#ifndef GEOID_NOT_AVAILABLE
+#define GEOID_NOT_AVAILABLE -1
+#endif
+
+/* This table maps Windows timezone keynames and countries per ISO 3166-1 to
+   POSIX-compatible timezone IDs.  The information is taken from
+   http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/zone_tzid.html
+
+   The mapping from unicode.org is just a bit incomplete.  It doesn't contain
+   a few timezones available on Windows XP, namely:
+
+    Armenian Standard Time
+    Mexico Standard Time
+    Mexico Standard Time 2
+
+  as well as the still (Windows 7) available
+
+    Mid-Atlantic Standard Time
+
+  It also doesn't contain some of the deprecated country codes used in older
+  OSes, namely:
+
+    SP (Serbian, proposed) used in XP
+    CS (Serbian and Montenegro, dissolved, now RS and ME) used in Vista
+
+  While these are apparently old, they are required here to get a complete
+  mapping on all supported OSes. */
+struct
+{
+  const char *win_tzkey;
+  const char *country;
+  const char *posix_tzid;
+} tzmap[] = 
+{
+  { "AUS Central Standard Time", "", "Australia/Darwin" },
+  { "AUS Central Standard Time", "AU", "Australia/Darwin" },
+  { "AUS Eastern Standard Time", "", "Australia/Sydney" },
+  { "AUS Eastern Standard Time", "AU", "Australia/Sydney Australia/Melbourne" },
+  { "Afghanistan Standard Time", "", "Asia/Kabul" },
+  { "Afghanistan Standard Time", "AF", "Asia/Kabul" },
+  { "Alaskan Standard Time", "", "America/Anchorage" },
+  { "Alaskan Standard Time", "US", "America/Anchorage America/Juneau America/Nome America/Sitka America/Yakutat" },
+  { "Arab Standard Time", "", "Asia/Riyadh" },
+  { "Arab Standard Time", "BH", "Asia/Bahrain" },
+  { "Arab Standard Time", "KW", "Asia/Kuwait" },
+  { "Arab Standard Time", "QA", "Asia/Qatar" },
+  { "Arab Standard Time", "SA", "Asia/Riyadh" },
+  { "Arab Standard Time", "YE", "Asia/Aden" },
+  { "Arabian Standard Time", "", "Asia/Dubai" },
+  { "Arabian Standard Time", "AE", "Asia/Dubai" },
+  { "Arabian Standard Time", "OM", "Asia/Muscat" },
+  { "Arabian Standard Time", "ZZ", "Etc/GMT-4" },
+  { "Arabic Standard Time", "", "Asia/Baghdad" },
+  { "Arabic Standard Time", "IQ", "Asia/Baghdad" },
+  { "Argentina Standard Time", "", "America/Buenos_Aires" },
+  { "Argentina Standard Time", "AR", "America/Buenos_Aires America/Argentina/La_Rioja America/Argentina/Rio_Gallegos America/Argentina/Salta America/Argentina/San_Juan America/Argentina/San_Luis America/Argentina/Tucuman America/Argentina/Ushuaia America/Catamarca America/Cordoba America/Jujuy America/Mendoza" },
+  { "Armenian Standard Time", "AM", "Asia/Yerevan" },
+  { "Atlantic Standard Time", "", "America/Halifax" },
+  { "Atlantic Standard Time", "BM", "Atlantic/Bermuda" },
+  { "Atlantic Standard Time", "CA", "America/Halifax America/Glace_Bay America/Goose_Bay America/Moncton" },
+  { "Atlantic Standard Time", "GL", "America/Thule" },
+  { "Azerbaijan Standard Time", "", "Asia/Baku" },
+  { "Azerbaijan Standard Time", "AZ", "Asia/Baku" },
+  { "Azores Standard Time", "", "Atlantic/Azores" },
+  { "Azores Standard Time", "GL", "America/Scoresbysund" },
+  { "Azores Standard Time", "PT", "Atlantic/Azores" },
+  { "Bahia Standard Time", "", "America/Bahia" },
+  { "Bahia Standard Time", "BR", "America/Bahia" },
+  { "Bangladesh Standard Time", "", "Asia/Dhaka" },
+  { "Bangladesh Standard Time", "BD", "Asia/Dhaka" },
+  { "Bangladesh Standard Time", "BT", "Asia/Thimphu" },
+  { "Canada Central Standard Time", "", "America/Regina" },
+  { "Canada Central Standard Time", "CA", "America/Regina America/Swift_Current" },
+  { "Cape Verde Standard Time", "", "Atlantic/Cape_Verde" },
+  { "Cape Verde Standard Time", "CV", "Atlantic/Cape_Verde" },
+  { "Cape Verde Standard Time", "ZZ", "Etc/GMT+1" },
+  { "Caucasus Standard Time", "", "Asia/Yerevan" },
+  { "Caucasus Standard Time", "AM", "Asia/Yerevan" },
+  { "Cen. Australia Standard Time", "", "Australia/Adelaide" },
+  { "Cen. Australia Standard Time", "AU", "Australia/Adelaide Australia/Broken_Hill" },
+  { "Central America Standard Time", "", "America/Guatemala" },
+  { "Central America Standard Time", "BZ", "America/Belize" },
+  { "Central America Standard Time", "CR", "America/Costa_Rica" },
+  { "Central America Standard Time", "EC", "Pacific/Galapagos" },
+  { "Central America Standard Time", "GT", "America/Guatemala" },
+  { "Central America Standard Time", "HN", "America/Tegucigalpa" },
+  { "Central America Standard Time", "NI", "America/Managua" },
+  { "Central America Standard Time", "SV", "America/El_Salvador" },
+  { "Central America Standard Time", "ZZ", "Etc/GMT+6" },
+  { "Central Asia Standard Time", "", "Asia/Almaty" },
+  { "Central Asia Standard Time", "AQ", "Antarctica/Vostok" },
+  { "Central Asia Standard Time", "IO", "Indian/Chagos" },
+  { "Central Asia Standard Time", "KG", "Asia/Bishkek" },
+  { "Central Asia Standard Time", "KZ", "Asia/Almaty Asia/Qyzylorda" },
+  { "Central Asia Standard Time", "ZZ", "Etc/GMT-6" },
+  { "Central Brazilian Standard Time", "", "America/Cuiaba" },
+  { "Central Brazilian Standard Time", "BR", "America/Cuiaba America/Campo_Grande" },
+  { "Central Europe Standard Time", "", "Europe/Budapest" },
+  { "Central Europe Standard Time", "AL", "Europe/Tirane" },
+  { "Central Europe Standard Time", "CS", "Europe/Belgrade" },
+  { "Central Europe Standard Time", "CZ", "Europe/Prague" },
+  { "Central Europe Standard Time", "HU", "Europe/Budapest" },
+  { "Central Europe Standard Time", "ME", "Europe/Podgorica" },
+  { "Central Europe Standard Time", "RS", "Europe/Belgrade" },
+  { "Central Europe Standard Time", "SI", "Europe/Ljubljana" },
+  { "Central Europe Standard Time", "SK", "Europe/Bratislava" },
+  { "Central Europe Standard Time", "SP", "Europe/Belgrade" },
+  { "Central European Standard Time", "", "Europe/Warsaw" },
+  { "Central European Standard Time", "BA", "Europe/Sarajevo" },
+  { "Central European Standard Time", "HR", "Europe/Zagreb" },
+  { "Central European Standard Time", "MK", "Europe/Skopje" },
+  { "Central European Standard Time", "PL", "Europe/Warsaw" },
+  { "Central Pacific Standard Time", "", "Pacific/Guadalcanal" },
+  { "Central Pacific Standard Time", "AQ", "Antarctica/Macquarie" },
+  { "Central Pacific Standard Time", "FM", "Pacific/Ponape Pacific/Kosrae" },
+  { "Central Pacific Standard Time", "NC", "Pacific/Noumea" },
+  { "Central Pacific Standard Time", "SB", "Pacific/Guadalcanal" },
+  { "Central Pacific Standard Time", "VU", "Pacific/Efate" },
+  { "Central Pacific Standard Time", "ZZ", "Etc/GMT-11" },
+  { "Central Standard Time", "", "America/Chicago" },
+  { "Central Standard Time", "CA", "America/Winnipeg America/Rainy_River America/Rankin_Inlet America/Resolute" },
+  { "Central Standard Time", "MX", "America/Matamoros" },
+  { "Central Standard Time", "US", "America/Chicago America/Indiana/Knox America/Indiana/Tell_City America/Menominee America/North_Dakota/Beulah America/North_Dakota/Center America/North_Dakota/New_Salem" },
+  { "Central Standard Time", "ZZ", "CST6CDT" },
+  { "Central Standard Time (Mexico)", "", "America/Mexico_City" },
+  { "Central Standard Time (Mexico)", "MX", "America/Mexico_City America/Bahia_Banderas America/Cancun America/Merida America/Monterrey" },
+  { "China Standard Time", "", "Asia/Shanghai" },
+  { "China Standard Time", "CN", "Asia/Shanghai Asia/Chongqing Asia/Harbin Asia/Kashgar Asia/Urumqi" },
+  { "China Standard Time", "HK", "Asia/Hong_Kong" },
+  { "China Standard Time", "MO", "Asia/Macau" },
+  { "Dateline Standard Time", "", "Etc/GMT+12" },
+  { "Dateline Standard Time", "ZZ", "Etc/GMT+12" },
+  { "E. Africa Standard Time", "", "Africa/Nairobi" },
+  { "E. Africa Standard Time", "AQ", "Antarctica/Syowa" },
+  { "E. Africa Standard Time", "DJ", "Africa/Djibouti" },
+  { "E. Africa Standard Time", "ER", "Africa/Asmera" },
+  { "E. Africa Standard Time", "ET", "Africa/Addis_Ababa" },
+  { "E. Africa Standard Time", "KE", "Africa/Nairobi" },
+  { "E. Africa Standard Time", "KM", "Indian/Comoro" },
+  { "E. Africa Standard Time", "MG", "Indian/Antananarivo" },
+  { "E. Africa Standard Time", "SD", "Africa/Khartoum" },
+  { "E. Africa Standard Time", "SO", "Africa/Mogadishu" },
+  { "E. Africa Standard Time", "SS", "Africa/Juba" },
+  { "E. Africa Standard Time", "TZ", "Africa/Dar_es_Salaam" },
+  { "E. Africa Standard Time", "UG", "Africa/Kampala" },
+  { "E. Africa Standard Time", "YT", "Indian/Mayotte" },
+  { "E. Africa Standard Time", "ZZ", "Etc/GMT-3" },
+  { "E. Australia Standard Time", "", "Australia/Brisbane" },
+  { "E. Australia Standard Time", "AU", "Australia/Brisbane Australia/Lindeman" },
+  { "E. Europe Standard Time", "", "Asia/Nicosia" },
+  { "E. Europe Standard Time", "CY", "Asia/Nicosia" },
+  { "E. South America Standard Time", "", "America/Sao_Paulo" },
+  { "E. South America Standard Time", "BR", "America/Sao_Paulo" },
+  { "Eastern Standard Time", "", "America/New_York" },
+  { "Eastern Standard Time", "BS", "America/Nassau" },
+  { "Eastern Standard Time", "CA", "America/Toronto America/Iqaluit America/Montreal America/Nipigon America/Pangnirtung America/Thunder_Bay" },
+  { "Eastern Standard Time", "TC", "America/Grand_Turk" },
+  { "Eastern Standard Time", "US", "America/New_York America/Detroit America/Indiana/Petersburg America/Indiana/Vincennes America/Indiana/Winamac America/Kentucky/Monticello America/Louisville" },
+  { "Eastern Standard Time", "ZZ", "EST5EDT" },
+  { "Egypt Standard Time", "", "Africa/Cairo" },
+  { "Egypt Standard Time", "EG", "Africa/Cairo" },
+  { "Egypt Standard Time", "PS", "Asia/Gaza Asia/Hebron" },
+  { "Ekaterinburg Standard Time", "", "Asia/Yekaterinburg" },
+  { "Ekaterinburg Standard Time", "RU", "Asia/Yekaterinburg" },
+  { "FLE Standard Time", "", "Europe/Kiev" },
+  { "FLE Standard Time", "AX", "Europe/Mariehamn" },
+  { "FLE Standard Time", "BG", "Europe/Sofia" },
+  { "FLE Standard Time", "EE", "Europe/Tallinn" },
+  { "FLE Standard Time", "FI", "Europe/Helsinki" },
+  { "FLE Standard Time", "LT", "Europe/Vilnius" },
+  { "FLE Standard Time", "LV", "Europe/Riga" },
+  { "FLE Standard Time", "UA", "Europe/Kiev Europe/Simferopol Europe/Uzhgorod Europe/Zaporozhye" },
+  { "Fiji Standard Time", "", "Pacific/Fiji" },
+  { "Fiji Standard Time", "FJ", "Pacific/Fiji" },
+  { "GMT Standard Time", "", "Europe/London" },
+  { "GMT Standard Time", "ES", "Atlantic/Canary" },
+  { "GMT Standard Time", "FO", "Atlantic/Faeroe" },
+  { "GMT Standard Time", "GB", "Europe/London" },
+  { "GMT Standard Time", "GG", "Europe/Guernsey" },
+  { "GMT Standard Time", "IE", "Europe/Dublin" },
+  { "GMT Standard Time", "IM", "Europe/Isle_of_Man" },
+  { "GMT Standard Time", "JE", "Europe/Jersey" },
+  { "GMT Standard Time", "PT", "Europe/Lisbon Atlantic/Madeira" },
+  { "GTB Standard Time", "", "Europe/Bucharest" },
+  { "GTB Standard Time", "GR", "Europe/Athens" },
+  { "GTB Standard Time", "MD", "Europe/Chisinau" },
+  { "GTB Standard Time", "RO", "Europe/Bucharest" },
+  { "Georgian Standard Time", "", "Asia/Tbilisi" },
+  { "Georgian Standard Time", "GE", "Asia/Tbilisi" },
+  { "Greenland Standard Time", "", "America/Godthab" },
+  { "Greenland Standard Time", "GL", "America/Godthab" },
+  { "Greenwich Standard Time", "", "Atlantic/Reykjavik" },
+  { "Greenwich Standard Time", "BF", "Africa/Ouagadougou" },
+  { "Greenwich Standard Time", "CI", "Africa/Abidjan" },
+  { "Greenwich Standard Time", "EH", "Africa/El_Aaiun" },
+  { "Greenwich Standard Time", "GH", "Africa/Accra" },
+  { "Greenwich Standard Time", "GM", "Africa/Banjul" },
+  { "Greenwich Standard Time", "GN", "Africa/Conakry" },
+  { "Greenwich Standard Time", "GW", "Africa/Bissau" },
+  { "Greenwich Standard Time", "IS", "Atlantic/Reykjavik" },
+  { "Greenwich Standard Time", "LR", "Africa/Monrovia" },
+  { "Greenwich Standard Time", "ML", "Africa/Bamako" },
+  { "Greenwich Standard Time", "MR", "Africa/Nouakchott" },
+  { "Greenwich Standard Time", "SH", "Atlantic/St_Helena" },
+  { "Greenwich Standard Time", "SL", "Africa/Freetown" },
+  { "Greenwich Standard Time", "SN", "Africa/Dakar" },
+  { "Greenwich Standard Time", "ST", "Africa/Sao_Tome" },
+  { "Greenwich Standard Time", "TG", "Africa/Lome" },
+  { "Hawaiian Standard Time", "", "Pacific/Honolulu" },
+  { "Hawaiian Standard Time", "CK", "Pacific/Rarotonga" },
+  { "Hawaiian Standard Time", "PF", "Pacific/Tahiti" },
+  { "Hawaiian Standard Time", "TK", "Pacific/Fakaofo" },
+  { "Hawaiian Standard Time", "UM", "Pacific/Johnston" },
+  { "Hawaiian Standard Time", "US", "Pacific/Honolulu" },
+  { "Hawaiian Standard Time", "ZZ", "Etc/GMT+10" },
+  { "India Standard Time", "", "Asia/Calcutta" },
+  { "India Standard Time", "IN", "Asia/Calcutta" },
+  { "Iran Standard Time", "", "Asia/Tehran" },
+  { "Iran Standard Time", "IR", "Asia/Tehran" },
+  { "Israel Standard Time", "", "Asia/Jerusalem" },
+  { "Israel Standard Time", "IL", "Asia/Jerusalem" },
+  { "Jordan Standard Time", "", "Asia/Amman" },
+  { "Jordan Standard Time", "JO", "Asia/Amman" },
+  { "Kaliningrad Standard Time", "", "Europe/Kaliningrad" },
+  { "Kaliningrad Standard Time", "BY", "Europe/Minsk" },
+  { "Kaliningrad Standard Time", "RU", "Europe/Kaliningrad" },
+  { "Kamchatka Standard Time", "", "Asia/Kamchatka" },
+  { "Korea Standard Time", "", "Asia/Seoul" },
+  { "Korea Standard Time", "KP", "Asia/Pyongyang" },
+  { "Korea Standard Time", "KR", "Asia/Seoul" },
+  { "Magadan Standard Time", "", "Asia/Magadan" },
+  { "Magadan Standard Time", "RU", "Asia/Magadan Asia/Anadyr Asia/Kamchatka" },
+  { "Mauritius Standard Time", "", "Indian/Mauritius" },
+  { "Mauritius Standard Time", "MU", "Indian/Mauritius" },
+  { "Mauritius Standard Time", "RE", "Indian/Reunion" },
+  { "Mauritius Standard Time", "SC", "Indian/Mahe" },
+  { "Mexico Standard Time", "", "America/Mexico_City" },
+  { "Mexico Standard Time 2", "", "America/Mazatlan" },
+  { "Mid-Atlantic Standard Time", "", "Atlantic/South_Georgia" },
+  { "Middle East Standard Time", "", "Asia/Beirut" },
+  { "Middle East Standard Time", "LB", "Asia/Beirut" },
+  { "Montevideo Standard Time", "", "America/Montevideo" },
+  { "Montevideo Standard Time", "UY", "America/Montevideo" },
+  { "Morocco Standard Time", "", "Africa/Casablanca" },
+  { "Morocco Standard Time", "MA", "Africa/Casablanca" },
+  { "Mountain Standard Time", "", "America/Denver" },
+  { "Mountain Standard Time", "CA", "America/Edmonton America/Cambridge_Bay America/Inuvik America/Yellowknife" },
+  { "Mountain Standard Time", "MX", "America/Ojinaga" },
+  { "Mountain Standard Time", "US", "America/Denver America/Boise America/Shiprock" },
+  { "Mountain Standard Time", "ZZ", "MST7MDT" },
+  { "Mountain Standard Time (Mexico)", "", "America/Chihuahua" },
+  { "Mountain Standard Time (Mexico)", "MX", "America/Chihuahua America/Mazatlan" },
+  { "Myanmar Standard Time", "", "Asia/Rangoon" },
+  { "Myanmar Standard Time", "CC", "Indian/Cocos" },
+  { "Myanmar Standard Time", "MM", "Asia/Rangoon" },
+  { "N. Central Asia Standard Time", "", "Asia/Novosibirsk" },
+  { "N. Central Asia Standard Time", "RU", "Asia/Novosibirsk Asia/Novokuznetsk Asia/Omsk" },
+  { "Namibia Standard Time", "", "Africa/Windhoek" },
+  { "Namibia Standard Time", "NA", "Africa/Windhoek" },
+  { "Nepal Standard Time", "", "Asia/Kathmandu" },
+  { "Nepal Standard Time", "NP", "Asia/Kathmandu" },
+  { "New Zealand Standard Time", "", "Pacific/Auckland" },
+  { "New Zealand Standard Time", "AQ", "Antarctica/South_Pole Antarctica/McMurdo" },
+  { "New Zealand Standard Time", "NZ", "Pacific/Auckland" },
+  { "Newfoundland Standard Time", "", "America/St_Johns" },
+  { "Newfoundland Standard Time", "CA", "America/St_Johns" },
+  { "North Asia East Standard Time", "", "Asia/Irkutsk" },
+  { "North Asia East Standard Time", "RU", "Asia/Irkutsk" },
+  { "North Asia Standard Time", "", "Asia/Krasnoyarsk" },
+  { "North Asia Standard Time", "RU", "Asia/Krasnoyarsk" },
+  { "Pacific SA Standard Time", "", "America/Santiago" },
+  { "Pacific SA Standard Time", "AQ", "Antarctica/Palmer" },
+  { "Pacific SA Standard Time", "CL", "America/Santiago" },
+  { "Pacific Standard Time", "", "America/Los_Angeles" },
+  { "Pacific Standard Time", "CA", "America/Vancouver America/Dawson America/Whitehorse" },
+  { "Pacific Standard Time", "MX", "America/Tijuana" },
+  { "Pacific Standard Time", "US", "America/Los_Angeles" },
+  { "Pacific Standard Time", "ZZ", "PST8PDT" },
+  { "Pacific Standard Time (Mexico)", "", "America/Santa_Isabel" },
+  { "Pacific Standard Time (Mexico)", "MX", "America/Santa_Isabel" },
+  { "Pakistan Standard Time", "", "Asia/Karachi" },
+  { "Pakistan Standard Time", "PK", "Asia/Karachi" },
+  { "Paraguay Standard Time", "", "America/Asuncion" },
+  { "Paraguay Standard Time", "PY", "America/Asuncion" },
+  { "Romance Standard Time", "", "Europe/Paris" },
+  { "Romance Standard Time", "BE", "Europe/Brussels" },
+  { "Romance Standard Time", "DK", "Europe/Copenhagen" },
+  { "Romance Standard Time", "ES", "Europe/Madrid Africa/Ceuta" },
+  { "Romance Standard Time", "FR", "Europe/Paris" },
+  { "Russian Standard Time", "", "Europe/Moscow" },
+  { "Russian Standard Time", "RU", "Europe/Moscow Europe/Samara Europe/Volgograd" },
+  { "SA Eastern Standard Time", "", "America/Cayenne" },
+  { "SA Eastern Standard Time", "AQ", "Antarctica/Rothera" },
+  { "SA Eastern Standard Time", "BR", "America/Fortaleza America/Araguaina America/Belem America/Maceio America/Recife America/Santarem" },
+  { "SA Eastern Standard Time", "GF", "America/Cayenne" },
+  { "SA Eastern Standard Time", "SR", "America/Paramaribo" },
+  { "SA Eastern Standard Time", "ZZ", "Etc/GMT+3" },
+  { "SA Pacific Standard Time", "", "America/Bogota" },
+  { "SA Pacific Standard Time", "CA", "America/Coral_Harbour" },
+  { "SA Pacific Standard Time", "CO", "America/Bogota" },
+  { "SA Pacific Standard Time", "EC", "America/Guayaquil" },
+  { "SA Pacific Standard Time", "HT", "America/Port-au-Prince" },
+  { "SA Pacific Standard Time", "JM", "America/Jamaica" },
+  { "SA Pacific Standard Time", "KY", "America/Cayman" },
+  { "SA Pacific Standard Time", "PA", "America/Panama" },
+  { "SA Pacific Standard Time", "PE", "America/Lima" },
+  { "SA Pacific Standard Time", "ZZ", "Etc/GMT+5" },
+  { "SA Western Standard Time", "", "America/La_Paz" },
+  { "SA Western Standard Time", "AG", "America/Antigua" },
+  { "SA Western Standard Time", "AI", "America/Anguilla" },
+  { "SA Western Standard Time", "AW", "America/Aruba" },
+  { "SA Western Standard Time", "BB", "America/Barbados" },
+  { "SA Western Standard Time", "BL", "America/St_Barthelemy" },
+  { "SA Western Standard Time", "BO", "America/La_Paz" },
+  { "SA Western Standard Time", "BR", "America/Manaus America/Boa_Vista America/Eirunepe America/Porto_Velho America/Rio_Branco" },
+  { "SA Western Standard Time", "CA", "America/Blanc-Sablon" },
+  { "SA Western Standard Time", "CW", "America/Curacao" },
+  { "SA Western Standard Time", "DM", "America/Dominica" },
+  { "SA Western Standard Time", "DO", "America/Santo_Domingo" },
+  { "SA Western Standard Time", "GD", "America/Grenada" },
+  { "SA Western Standard Time", "GP", "America/Guadeloupe" },
+  { "SA Western Standard Time", "GY", "America/Guyana" },
+  { "SA Western Standard Time", "KN", "America/St_Kitts" },
+  { "SA Western Standard Time", "LC", "America/St_Lucia" },
+  { "SA Western Standard Time", "MF", "America/Marigot" },
+  { "SA Western Standard Time", "MQ", "America/Martinique" },
+  { "SA Western Standard Time", "MS", "America/Montserrat" },
+  { "SA Western Standard Time", "PR", "America/Puerto_Rico" },
+  { "SA Western Standard Time", "TT", "America/Port_of_Spain" },
+  { "SA Western Standard Time", "VC", "America/St_Vincent" },
+  { "SA Western Standard Time", "VG", "America/Tortola" },
+  { "SA Western Standard Time", "VI", "America/St_Thomas" },
+  { "SA Western Standard Time", "ZZ", "Etc/GMT+4" },
+  { "SE Asia Standard Time", "", "Asia/Bangkok" },
+  { "SE Asia Standard Time", "AQ", "Antarctica/Davis" },
+  { "SE Asia Standard Time", "CX", "Indian/Christmas" },
+  { "SE Asia Standard Time", "ID", "Asia/Jakarta Asia/Pontianak" },
+  { "SE Asia Standard Time", "KH", "Asia/Phnom_Penh" },
+  { "SE Asia Standard Time", "LA", "Asia/Vientiane" },
+  { "SE Asia Standard Time", "MN", "Asia/Hovd" },
+  { "SE Asia Standard Time", "TH", "Asia/Bangkok" },
+  { "SE Asia Standard Time", "VN", "Asia/Saigon" },
+  { "SE Asia Standard Time", "ZZ", "Etc/GMT-7" },
+  { "Samoa Standard Time", "", "Pacific/Apia" },
+  { "Samoa Standard Time", "WS", "Pacific/Apia" },
+  { "Singapore Standard Time", "", "Asia/Singapore" },
+  { "Singapore Standard Time", "BN", "Asia/Brunei" },
+  { "Singapore Standard Time", "ID", "Asia/Makassar" },
+  { "Singapore Standard Time", "MY", "Asia/Kuala_Lumpur Asia/Kuching" },
+  { "Singapore Standard Time", "PH", "Asia/Manila" },
+  { "Singapore Standard Time", "SG", "Asia/Singapore" },
+  { "Singapore Standard Time", "ZZ", "Etc/GMT-8" },
+  { "South Africa Standard Time", "", "Africa/Johannesburg" },
+  { "South Africa Standard Time", "BI", "Africa/Bujumbura" },
+  { "South Africa Standard Time", "BW", "Africa/Gaborone" },
+  { "South Africa Standard Time", "CD", "Africa/Lubumbashi" },
+  { "South Africa Standard Time", "LS", "Africa/Maseru" },
+  { "South Africa Standard Time", "LY", "Africa/Tripoli" },
+  { "South Africa Standard Time", "MW", "Africa/Blantyre" },
+  { "South Africa Standard Time", "MZ", "Africa/Maputo" },
+  { "South Africa Standard Time", "RW", "Africa/Kigali" },
+  { "South Africa Standard Time", "SZ", "Africa/Mbabane" },
+  { "South Africa Standard Time", "ZA", "Africa/Johannesburg" },
+  { "South Africa Standard Time", "ZM", "Africa/Lusaka" },
+  { "South Africa Standard Time", "ZW", "Africa/Harare" },
+  { "South Africa Standard Time", "ZZ", "Etc/GMT-2" },
+  { "Sri Lanka Standard Time", "", "Asia/Colombo" },
+  { "Sri Lanka Standard Time", "LK", "Asia/Colombo" },
+  { "Syria Standard Time", "", "Asia/Damascus" },
+  { "Syria Standard Time", "SY", "Asia/Damascus" },
+  { "Taipei Standard Time", "", "Asia/Taipei" },
+  { "Taipei Standard Time", "TW", "Asia/Taipei" },
+  { "Tasmania Standard Time", "", "Australia/Hobart" },
+  { "Tasmania Standard Time", "AU", "Australia/Hobart Australia/Currie" },
+  { "Tokyo Standard Time", "", "Asia/Tokyo" },
+  { "Tokyo Standard Time", "ID", "Asia/Jayapura" },
+  { "Tokyo Standard Time", "JP", "Asia/Tokyo" },
+  { "Tokyo Standard Time", "PW", "Pacific/Palau" },
+  { "Tokyo Standard Time", "TL", "Asia/Dili" },
+  { "Tokyo Standard Time", "ZZ", "Etc/GMT-9" },
+  { "Tonga Standard Time", "", "Pacific/Tongatapu" },
+  { "Tonga Standard Time", "KI", "Pacific/Enderbury" },
+  { "Tonga Standard Time", "TO", "Pacific/Tongatapu" },
+  { "Tonga Standard Time", "ZZ", "Etc/GMT-13" },
+  { "Turkey Standard Time", "", "Europe/Istanbul" },
+  { "Turkey Standard Time", "TR", "Europe/Istanbul" },
+  { "US Eastern Standard Time", "", "America/Indianapolis" },
+  { "US Eastern Standard Time", "US", "America/Indianapolis America/Indiana/Marengo America/Indiana/Vevay" },
+  { "US Mountain Standard Time", "", "America/Phoenix" },
+  { "US Mountain Standard Time", "CA", "America/Dawson_Creek" },
+  { "US Mountain Standard Time", "MX", "America/Hermosillo" },
+  { "US Mountain Standard Time", "US", "America/Phoenix" },
+  { "US Mountain Standard Time", "ZZ", "Etc/GMT+7" },
+  { "UTC", "", "Etc/GMT" },
+  { "UTC", "GL", "America/Danmarkshavn" },
+  { "UTC", "ZZ", "Etc/GMT" },
+  { "UTC+12", "", "Etc/GMT-12" },
+  { "UTC+12", "KI", "Pacific/Tarawa" },
+  { "UTC+12", "MH", "Pacific/Majuro Pacific/Kwajalein" },
+  { "UTC+12", "NR", "Pacific/Nauru" },
+  { "UTC+12", "TV", "Pacific/Funafuti" },
+  { "UTC+12", "UM", "Pacific/Wake" },
+  { "UTC+12", "WF", "Pacific/Wallis" },
+  { "UTC+12", "ZZ", "Etc/GMT-12" },
+  { "UTC-02", "", "Etc/GMT+2" },
+  { "UTC-02", "BR", "America/Noronha" },
+  { "UTC-02", "GS", "Atlantic/South_Georgia" },
+  { "UTC-02", "ZZ", "Etc/GMT+2" },
+  { "UTC-11", "", "Etc/GMT+11" },
+  { "UTC-11", "AS", "Pacific/Pago_Pago" },
+  { "UTC-11", "NU", "Pacific/Niue" },
+  { "UTC-11", "UM", "Pacific/Midway" },
+  { "UTC-11", "ZZ", "Etc/GMT+11" },
+  { "Ulaanbaatar Standard Time", "", "Asia/Ulaanbaatar" },
+  { "Ulaanbaatar Standard Time", "MN", "Asia/Ulaanbaatar Asia/Choibalsan" },
+  { "Venezuela Standard Time", "", "America/Caracas" },
+  { "Venezuela Standard Time", "VE", "America/Caracas" },
+  { "Vladivostok Standard Time", "", "Asia/Vladivostok" },
+  { "Vladivostok Standard Time", "RU", "Asia/Vladivostok Asia/Sakhalin" },
+  { "W. Australia Standard Time", "", "Australia/Perth" },
+  { "W. Australia Standard Time", "AQ", "Antarctica/Casey" },
+  { "W. Australia Standard Time", "AU", "Australia/Perth" },
+  { "W. Central Africa Standard Time", "", "Africa/Lagos" },
+  { "W. Central Africa Standard Time", "AO", "Africa/Luanda" },
+  { "W. Central Africa Standard Time", "BJ", "Africa/Porto-Novo" },
+  { "W. Central Africa Standard Time", "CD", "Africa/Kinshasa" },
+  { "W. Central Africa Standard Time", "CF", "Africa/Bangui" },
+  { "W. Central Africa Standard Time", "CG", "Africa/Brazzaville" },
+  { "W. Central Africa Standard Time", "CM", "Africa/Douala" },
+  { "W. Central Africa Standard Time", "DZ", "Africa/Algiers" },
+  { "W. Central Africa Standard Time", "GA", "Africa/Libreville" },
+  { "W. Central Africa Standard Time", "GQ", "Africa/Malabo" },
+  { "W. Central Africa Standard Time", "NE", "Africa/Niamey" },
+  { "W. Central Africa Standard Time", "NG", "Africa/Lagos" },
+  { "W. Central Africa Standard Time", "TD", "Africa/Ndjamena" },
+  { "W. Central Africa Standard Time", "TN", "Africa/Tunis" },
+  { "W. Central Africa Standard Time", "ZZ", "Etc/GMT-1" },
+  { "W. Europe Standard Time", "", "Europe/Berlin" },
+  { "W. Europe Standard Time", "AD", "Europe/Andorra" },
+  { "W. Europe Standard Time", "AT", "Europe/Vienna" },
+  { "W. Europe Standard Time", "CH", "Europe/Zurich" },
+  { "W. Europe Standard Time", "DE", "Europe/Berlin" },
+  { "W. Europe Standard Time", "GI", "Europe/Gibraltar" },
+  { "W. Europe Standard Time", "IT", "Europe/Rome" },
+  { "W. Europe Standard Time", "LI", "Europe/Vaduz" },
+  { "W. Europe Standard Time", "LU", "Europe/Luxembourg" },
+  { "W. Europe Standard Time", "MC", "Europe/Monaco" },
+  { "W. Europe Standard Time", "MT", "Europe/Malta" },
+  { "W. Europe Standard Time", "NL", "Europe/Amsterdam" },
+  { "W. Europe Standard Time", "NO", "Europe/Oslo" },
+  { "W. Europe Standard Time", "SE", "Europe/Stockholm" },
+  { "W. Europe Standard Time", "SJ", "Arctic/Longyearbyen" },
+  { "W. Europe Standard Time", "SM", "Europe/San_Marino" },
+  { "W. Europe Standard Time", "VA", "Europe/Vatican" },
+  { "West Asia Standard Time", "", "Asia/Tashkent" },
+  { "West Asia Standard Time", "AQ", "Antarctica/Mawson" },
+  { "West Asia Standard Time", "KZ", "Asia/Oral Asia/Aqtau Asia/Aqtobe" },
+  { "West Asia Standard Time", "MV", "Indian/Maldives" },
+  { "West Asia Standard Time", "TF", "Indian/Kerguelen" },
+  { "West Asia Standard Time", "TJ", "Asia/Dushanbe" },
+  { "West Asia Standard Time", "TM", "Asia/Ashgabat" },
+  { "West Asia Standard Time", "UZ", "Asia/Tashkent Asia/Samarkand" },
+  { "West Asia Standard Time", "ZZ", "Etc/GMT-5" },
+  { "West Pacific Standard Time", "", "Pacific/Port_Moresby" },
+  { "West Pacific Standard Time", "AQ", "Antarctica/DumontDUrville" },
+  { "West Pacific Standard Time", "FM", "Pacific/Truk" },
+  { "West Pacific Standard Time", "GU", "Pacific/Guam" },
+  { "West Pacific Standard Time", "MP", "Pacific/Saipan" },
+  { "West Pacific Standard Time", "PG", "Pacific/Port_Moresby" },
+  { "West Pacific Standard Time", "ZZ", "Etc/GMT-10" },
+  { "Yakutsk Standard Time", "", "Asia/Yakutsk" },
+  { "Yakutsk Standard Time", "RU", "Asia/Yakutsk" }
+};
+
+#define TZMAP_SIZE (sizeof tzmap / sizeof tzmap[0])
+
+static struct option longopts[] =
+{
+  {"help", no_argument, NULL, 'h' },
+  {"version", no_argument, NULL, 'V'},
+  {NULL, 0, NULL, 0}
+};
+
+static char opts[] = "hV";
+
+#define REG_TZINFO "SYSTEM\\CurrentControlSet\\Control\\TimeZoneInformation"
+#define REG_TZDB   "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Time Zones"
+
+/* Not available on pre-XP */
+GEOID WINAPI (*getusergeoid)(GEOCLASS);
+int WINAPI (*getgeoinfo)(GEOID, GEOTYPE, LPTSTR, int, LANGID);
+
+static inline HKEY
+reg_open (HKEY pkey, const char *path, const char *msg)
+{
+  LONG ret;
+  HKEY hkey;
+
+  ret = RegOpenKeyEx (pkey, path, 0, KEY_READ, &hkey);
+  if (ret == ERROR_SUCCESS)
+    return hkey;
+  if (msg)
+    fprintf (stderr, "%s: cannot open registry %s, error code %ld\n",
+	     program_invocation_short_name, msg, ret);
+  return NULL;
+}
+
+/* For symmetry */
+#define reg_close(hkey)	RegCloseKey(hkey)
+
+static inline BOOL
+reg_query (HKEY hkey, const char *value, char *buf, DWORD size, const char *msg)
+{
+  LONG ret;
+  DWORD type;
+
+  ret = RegQueryValueEx (hkey, value, 0, &type, (LPBYTE) buf, &size);
+  if (ret == ERROR_SUCCESS)
+    return TRUE;
+  if (msg)
+    fprintf (stderr, "%s: cannot query registry %s, error code %ld\n",
+	     program_invocation_short_name, msg, ret);
+  return FALSE;
+}
+
+static inline BOOL
+reg_enum (HKEY hkey, int idx, char *name, DWORD size)
+{
+  return RegEnumKeyEx (hkey, idx, name, &size, NULL, NULL, NULL, NULL)
+	 == ERROR_SUCCESS;
+}
+
+static void
+usage (FILE *stream)
+{
+  fprintf (stream, ""
+  "Usage: %1$s [OPTION]\n"
+  "\n"
+  "Print POSIX-compatible timezone ID from current Windows timezone setting\n"
+  "\n"
+  "Options:\n"
+  "  -h, --help               output usage information and exit.\n"
+  "  -V, --version            output version information and exit.\n"
+  "\n"
+  "Use %1$s to set your TZ variable. In POSIX-compatible shells like bash,\n"
+  "dash, mksh, or zsh:\n"
+  "\n"
+  "      export TZ=$(%1$s)\n"
+  "\n"
+  "In csh-compatible shells like tcsh:\n"
+  "\n"
+  "      setenv TZ `%1$s`\n"
+  "\n", program_invocation_short_name);
+};
+
+static void
+print_version ()
+{
+  printf ("tzset (cygwin) %d.%d.%d\n"
+	  "POSIX-timezone generator\n"
+	  "Copyright (C) 2012 - %s Red Hat, Inc.\n"
+	  "This is free software; see the source for copying conditions.  There is NO\n"
+	  "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n",
+	  CYGWIN_VERSION_DLL_MAJOR / 1000,
+	  CYGWIN_VERSION_DLL_MAJOR % 1000,
+	  CYGWIN_VERSION_DLL_MINOR,
+	  strrchr (__DATE__, ' ') + 1);
+}
+
+int
+main (int argc, char **argv)
+{
+  BOOL ret;
+  HKEY hkey, skey;
+  char keyname[256], stdname[256], std2name[256], country[10], *spc;
+  GEOID geo;
+  int opt, idx, gotit = -1;
+
+  while ((opt = getopt_long (argc, argv, opts, longopts, NULL)) != EOF)
+    switch (opt)
+      {
+      case 'h':
+	usage (stdout);
+	return 0;
+      case 'V':
+	print_version ();
+	return 0;
+      default:
+	fprintf (stderr, "Try `%s --help' for more information.\n",
+		 program_invocation_short_name);
+	return 1;
+      }
+  if (optind < argc)
+    {
+	usage (stderr);
+	return 1;
+    }
+
+  /* First fetch current timezone information from registry. */
+  hkey = reg_open (HKEY_LOCAL_MACHINE, REG_TZINFO, "timezone information");
+  if (!hkey)
+    return 1;
+  /* Vista introduced the TimeZoneKeyName value, which simplifies the
+     job a lot. */
+  if (!reg_query (hkey, "TimeZoneKeyName", keyname, sizeof keyname, NULL))
+    {
+      /* Pre-Vista we have a lot more to do.  First fetch the name of the
+	 Standard (non-DST) timezone.  If we can't get that, give up. */
+      if (!reg_query (hkey, "StandardName", stdname, sizeof stdname,
+		      "timezone information"))
+	{
+	  reg_close (hkey);
+	  return 1;
+	}
+      reg_close (hkey);
+      /* Now open the timezone database registry key.  Every subkey is a
+         timezone.  The key name is what we're after, but to find the right
+	 one, we have to compare the name of the previously fetched
+	 "StandardName" with the "Std" value in the timezone info... */
+      hkey = reg_open (HKEY_LOCAL_MACHINE, REG_TZDB, "timezone database");
+      if (!hkey)
+	return 1;
+      for (idx = 0; reg_enum (hkey, idx, keyname, sizeof keyname); ++idx)
+	{
+	  skey = reg_open (hkey, keyname, NULL);
+	  if (skey)
+	    {
+	      /* ...however, on MUI-enabled machines, the names are not stored
+		 directly in the above StandardName, rather it is a resource
+		 pointer into tzres.dll.  This is stored in MUI_Std.
+		 Fortunately it's easy to recognize this situation: If
+		 StandardName starts with @, it's a resource pointer, otherwise
+		 it's the cleartext value. */
+	      ret = reg_query (skey, stdname[0] == '@' ? "MUI_Std" : "Std",
+			       std2name, sizeof std2name, NULL);
+	      reg_close (skey);
+	      if (ret && !strcmp (stdname, std2name))
+		break;
+	    }
+	}
+    }
+  reg_close (hkey);
+
+  /* Fetch addresses of Geo functions.  As long as we support Windows 2000
+     this is required, unfortunately. */
+  getusergeoid = (GEOID (WINAPI *)())
+  		 GetProcAddress (GetModuleHandle ("kernel32.dll"),
+				 "GetUserGeoID");
+  getgeoinfo = (int (WINAPI *)(GEOID, GEOTYPE, LPTSTR, int, LANGID))
+	       GetProcAddress (GetModuleHandle ("kernel32.dll"),
+			       "GetGeoInfoA");
+  *country = '\0';
+  /* Post-W2K we fetch the current Geo-location of the user and convert it
+     to a ISO 3166-1 compatible nation code. */
+  if (getusergeoid && getgeoinfo)
+    {
+      geo = getusergeoid (GEOCLASS_NATION);
+      if (geo != GEOID_NOT_AVAILABLE)
+	getgeoinfo (geo, GEO_ISO2, country, sizeof country, 0);
+    }
+  /* On W2K, or if the Geo-location isn't available, we use the locale
+     setting instead. */
+  if (!*country)
+    GetLocaleInfo (LOCALE_USER_DEFAULT, LOCALE_SISO3166CTRYNAME,
+		   country, sizeof country);
+
+  /* Now iterate over the mapping table and find the right entry. */
+  for (idx = 0; idx < TZMAP_SIZE; ++idx)
+    {
+      if (!strcmp (keyname, tzmap[idx].win_tzkey))
+	{
+	  if (gotit < 0)
+	    gotit = idx;
+	  if (!strcmp (country, tzmap[idx].country))
+	    break;
+	}
+      else if (gotit >= 0)
+	{
+	  idx = gotit;
+	  break;
+	}
+    }
+  if (idx >= TZMAP_SIZE)
+    {
+      if (gotit < 0)
+	{
+	  fprintf (stderr,
+		   "%s: can't find matching POSIX timezone for "
+		   "Windows timezone \"%s\"\n",
+		   program_invocation_short_name, keyname);
+	  return 1;
+	}
+      idx = gotit;
+    }
+  /* Got one.  Print it. */
+  spc = strchr (tzmap[idx].posix_tzid, ' ');
+  if (spc)
+    *spc = '\0';
+  printf ("%s\n", tzmap[idx].posix_tzid);
+  return 0;
+}
diff --git a/winsup/utils/utils.sgml b/winsup/utils/utils.sgml
index f6d3a5158..aa8fe0f11 100644
--- a/winsup/utils/utils.sgml
+++ b/winsup/utils/utils.sgml
@@ -2117,6 +2117,34 @@ This program is mainly useful for debugging the Cygwin DLL itself.</para>
 
 </sect2>
 
+<sect2 id="tzset"><title>tzset</title>
+
+<screen>
+Usage: tzset [OPTION]
+
+Print POSIX-compatible timezone ID from current Windows timezone setting
+
+Options:
+  -h, --help               output usage information and exit.
+  -V, --version            output version information and exit.
+
+Use tzset to set your TZ variable. In POSIX-compatible shells like bash,
+dash, mksh, or zsh:
+
+      export TZ=$(tzset)
+
+In csh-compatible shells like tcsh:
+
+      setenv TZ `tzset`
+</screen>
+
+<para>The <command>tzset</command> tool reads the current timezone from Windows
+and generates a POSIX-compatible timezone information for the TZ environment
+variable from that information.  That's all there is to it.  For the way how
+to use it, see the above usage information.</para>
+
+</sect2>
+
 <sect2 id="umount"><title>umount</title>
 
 <screen>