[gnome-control-center/gnome-3-0] datetime: Restore TZ envvar as it was

[Bastien Nocera <hadess src gnome org>]

commit f38e11d3a744bd7efba4ed9d77664ad803790473
Author: Rui Matos <tiagomatos gmail com>
Date:   Fri Jun 24 03:41:32 2011 +0100

    datetime: Restore TZ envvar as it was
    
    tz_info_from_location() was changing the value of TZ, but not
    restoring it when it was done checking data for it, and setting
    the GMT timezone instead.
    
    This meant that UTC time was displayed when the minute changed on
    the wall clock.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=649568

 panels/datetime/tz.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)
---
diff --git a/panels/datetime/tz.c b/panels/datetime/tz.c
index 776418b..c539d59 100644
--- a/panels/datetime/tz.c
+++ b/panels/datetime/tz.c
@@ -203,10 +203,12 @@ tz_info_from_location (TzLocation *loc)
 	TzInfo *tzinfo;
 	time_t curtime;
 	struct tm *curzone;
+	gchar *tz_env_value;
 	
 	g_return_val_if_fail (loc != NULL, NULL);
 	g_return_val_if_fail (loc->zone != NULL, NULL);
 	
+	tz_env_value = g_strdup (getenv ("TZ"));
 	setenv ("TZ", loc->zone, 1);
 	
 #if 0
@@ -236,7 +238,12 @@ tz_info_from_location (TzLocation *loc)
 
 	tzinfo->daylight = curzone->tm_isdst;
 
-	setenv ("TZ", "", 1);
+	if (tz_env_value)
+		setenv ("TZ", tz_env_value, 1);
+	else
+		unsetenv ("TZ");
+
+	g_free (tz_env_value);
 	
 	return tzinfo;
 }