Index: system/system.install
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.install,v
retrieving revision 1.88
diff -u -r1.88 system.install
--- system/system.install	30 Mar 2007 08:47:58 -0000	1.88
+++ system/system.install	6 Apr 2007 12:10:44 -0000
@@ -559,6 +559,7 @@
         login int NOT NULL default '0',
         status tinyint NOT NULL default '0',
         timezone varchar(8) default NULL,
+        zonename varchar(50) default NULL,
         language varchar(12) NOT NULL default '',
         picture varchar(255) NOT NULL DEFAULT '',
         init varchar(64) default '',
@@ -1045,6 +1046,7 @@
         login int NOT NULL default '0',
         status smallint NOT NULL default '0',
         timezone varchar(8) default NULL,
+        zonename varchar(50) default NULL,
         language varchar(12) NOT NULL default '',
         picture varchar(255) NOT NULL DEFAULT '',
         init varchar(64) default '',
@@ -3724,6 +3726,23 @@
 }
 
 /**
+ * Add timezone name column to users table.
+ */
+function system_update_2007() {
+  $ret = array();
+  switch ($GLOBALS['db_type']) {
+    case 'pgsql':
+      db_add_column($ret, 'users', 'zonename', 'varchar(50)', array('not null' => FALSE));
+      break;
+    case 'mysql':
+    case 'mysqli':
+      $ret[] = update_sql("ALTER TABLE {users} ADD zonename varchar(50) NULL");
+      break;
+  }
+  return $ret;
+}
+
+/**
  * @} End of "defgroup updates-5.0-to-x.x"
  * The next series of updates should start at 3000.
  */
Index: system/system.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.module,v
retrieving revision 1.461
diff -u -r1.461 system.module
--- system/system.module	6 Apr 2007 04:39:51 -0000	1.461
+++ system/system.module	6 Apr 2007 12:08:35 -0000
@@ -307,6 +307,14 @@
   drupal_add_css(drupal_get_path('module', 'system') .'/system.css', 'module');
 }
 
+function system_cron() {
+  if (drupal_handle_timezones() && variable_get('date_timezone_next_update', 0) <= time()) {
+    system_timezone_update_site();
+    system_timezone_update_user();
+    variable_set('date_timezone_next_update', time() + 86400);
+  }
+}
+
 /**
  * Implementation of hook_user().
  *
@@ -317,23 +325,36 @@
     $form['theme_select'] = system_theme_select_form(t('Selecting a different theme will change the look and feel of the site.'), isset($edit['theme']) ? $edit['theme'] : NULL, 2);
 
     if (variable_get('configurable_timezones', 1)) {
-      $zones = _system_zonelist();
       $form['timezone'] = array(
         '#type'=>'fieldset',
         '#title' => t('Locale settings'),
         '#weight' => 6,
         '#collapsible' => TRUE,
       );
-      $form['timezone']['timezone'] = array(
-        '#type' => 'select',
-        '#title' => t('Time zone'),
-        '#default_value' => strlen($edit['timezone']) ? $edit['timezone'] : variable_get('date_default_timezone', 0),
-        '#options' => $zones,
-        '#description' => t('Select your current local time. Dates and times throughout this site will be displayed using this time zone.'),
-      );
+      if (drupal_handle_timezones()) {
+        $form['timezone']['zonename'] = array(
+          '#type' => 'select',
+          '#title' => t('Time zone'),
+          '#default_value' => strlen($edit['zonename']) ? $edit['zonename'] : variable_get('date_default_zonename', 'GMT'),
+          '#options' => system_zonenames(),
+          '#description' => t('Select your current local time zone. Dates and times throughout this site will be displayed using this time zone.'),
+        );
+      }
+      else {
+        $form['timezone']['timezone'] = array(
+          '#type' => 'select',
+          '#title' => t('Time zone'),
+          '#default_value' => strlen($edit['timezone']) ? $edit['timezone'] : variable_get('date_default_timezone', 0),
+          '#options' => _system_zonelist(),
+          '#description' => t('Select your current local time. Dates and times throughout this site will be displayed using this time zone.'),
+        );
+      }
     }
-
     return $form;
+
+  }
+  elseif ($type == 'submit' && drupal_handle_timezones()) {
+    system_timezone_update_user($user->uid, $edit['zonename']);
   }
 }
 
@@ -515,6 +536,11 @@
   return $output;
 }
 
+function drupal_handle_timezones() {
+  // This may need more than just a version comparison. Some libraries might be missing even in the right version.
+	return version_compare(PHP_VERSION, '5.1', '>=');
+}
+
 function _system_zonelist() {
   $timestamp = time();
   $zonelist = array(-11, -10, -9.5, -9, -8, -7, -6, -5, -4, -3.5, -3, -2, -1, 0, 1, 2, 3, 3.5, 4, 5, 5.5, 5.75, 6, 6.5, 7, 8, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.75, 13, 14);
@@ -526,6 +552,47 @@
   return $zones;
 }
 
+function system_zonenames() {
+  if (drupal_handle_timezones()) {
+    return drupal_map_assoc(DateTimeZone::listIdentifiers());
+  }
+}
+
+function system_timezone_update_site($zonename = '') {
+  if (drupal_handle_timezones()) {
+    if (!empty($zonename)) {
+      variable_set('date_default_zonename', $zonename);
+    }
+    else {
+      $zonename = variable_get('date_default_zonename', 'GMT');
+    }
+    $dateTimeZone = new DateTimeZone($zonename);
+    $dateTime = new DateTime("now", $dateTimeZone);
+    variable_set('date_default_timezone', $dateTimeZone->getOffset($dateTime));
+    // Do we want to do date_default_timezone_set()? This will make all php date functions use this timezone
+    // which may affect logs and statistics. See http://us3.php.net/manual/en/function.date-default-timezone-set.php.
+    date_default_timezone_set($zonename);
+  }
+}
+
+function system_timezone_update_user($uid = 0, $zonename = '') {
+  if (drupal_handle_timezones()) {
+    if (!empty($uid) && !empty($zonename)) {
+      $dateTimeZone = new DateTimeZone($zonename);
+      $dateTime = new DateTime("now", $dateTimeZone);
+      db_query("UPDATE {users} SET zonename = '%s', timezone = '%s' WHERE uid = %d", $zonename, $dateTimeZone->getOffset($dateTime), $uid);
+    }
+    else {
+      $result = db_query("SELECT DISTINCT zonename FROM {users}");
+      while ($row = db_fetch_array($result)) {
+        $dateTimeZone = new DateTimeZone($row['zonename']);
+        $dateTime = new DateTime("now", $dateTimeZone);
+        db_query("UPDATE {users} SET timezone = '%s' WHERE zonename = '%s'", $dateTimeZone->getOffset($dateTime), $row['zonename']);
+      }
+    }
+  }
+}
+
 function system_site_information_settings() {
   $form['site_name'] = array(
     '#type' => 'textfield',
@@ -781,7 +848,6 @@
 
 function system_date_time_settings() {
   // Date settings:
-  $zones = _system_zonelist();
 
   // Date settings: possible date formats
   $dateshort = array('Y-m-d H:i', 'm/d/Y - H:i', 'd/m/Y - H:i', 'Y/m/d - H:i',
@@ -806,13 +872,33 @@
     $datelongchoices[$f] = format_date(time(), 'custom', $f);
   }
 
-  $form['date_default_timezone'] = array(
-    '#type' => 'select',
-    '#title' => t('Default time zone'),
-    '#default_value' => variable_get('date_default_timezone', 0),
-    '#options' => $zones,
-    '#description' => t('Select the default site time zone.')
-  );
+  if (drupal_handle_timezones()) {
+    $form['date_default_timezone'] = array(
+      '#type' => 'hidden',
+      '#value' => variable_get('date_default_timezone', 0),
+    );
+    $form['date_default_zonename'] = array(
+      '#type' => 'select',
+      '#title' => t('Default time zone'),
+      '#default_value' => variable_get('date_default_zonename', 'GMT'),
+      '#options' => system_zonenames(),
+      '#description' => t('Select the default site time zone.'),
+      '#submit' => array('system_timezone_update_site' => array('date_default_zonename')),
+    );
+  }
+  else {
+    $form['date_default_zonename'] = array(
+      '#type' => 'hidden',
+      '#value' => variable_get('date_default_zonename', 'GMT'),
+    );
+    $form['date_default_timezone'] = array(
+      '#type' => 'select',
+      '#title' => t('Default time zone'),
+      '#default_value' => variable_get('date_default_timezone', 0),
+      '#options' => _system_zonelist(),
+      '#description' => t('Select the default site time zone.'),
+    );
+  }
 
   $form['configurable_timezones'] = array(
     '#type' => 'radios',
@@ -2397,4 +2483,4 @@
   $output .= '</div>';
 
   return $output;
-}
+}
\ No newline at end of file
Index: user/user.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/user/user.module,v
retrieving revision 1.763
diff -u -r1.763 user.module
--- user/user.module	30 Mar 2007 07:45:19 -0000	1.763
+++ user/user.module	6 Apr 2007 11:00:44 -0000
@@ -398,7 +398,7 @@
     }
     else {
       // Make sure we return the default fields at least
-      $fields = array('uid', 'name', 'pass', 'mail', 'picture', 'mode', 'sort', 'threshold', 'theme', 'signature', 'created', 'access', 'login', 'status', 'timezone', 'language', 'init', 'data');
+      $fields = array('uid', 'name', 'pass', 'mail', 'picture', 'mode', 'sort', 'threshold', 'theme', 'signature', 'created', 'access', 'login', 'status', 'timezone', 'zonename', 'language', 'init', 'data');
     }
   }