[glib] GDateTime: Add guards to g_date_time_new()

[Matthias Clasen <matthiasc src gnome org>]

commit 88b284c07051ccf5a7561d04236d83c8bb61993a
Author: Bastien Nocera <hadess hadess net>
Date:   Thu Apr 17 09:18:14 2014 +0200

    GDateTime: Add guards to g_date_time_new()
    
    https://bugzilla.gnome.org/show_bug.cgi?id=728401

 glib/gdatetime.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/glib/gdatetime.c b/glib/gdatetime.c
index 2d20679..cbbf620 100644
--- a/glib/gdatetime.c
+++ b/glib/gdatetime.c
@@ -944,6 +944,8 @@ g_date_time_new (GTimeZone *tz,
   GDateTime *datetime;
   gint64 full_time;
 
+  g_return_val_if_fail (tz != NULL, NULL);
+
   if (year < 1 || year > 9999 ||
       month < 1 || month > 12 ||
       day < 1 || day > 31 ||