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

[Bastien Nocera <hadess src gnome org>]

commit 11d94b271b85b6146166ac1839ead7de6e5956d9
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;
 }