[gtk+] Fix return_if_fail lines in gtk_box_pack

[Matthias Clasen <matthiasc src gnome org>]

commit e734b79fd82ee0c21ff4b38d350c0aabb7949447
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Feb 17 11:54:43 2014 -0500

    Fix return_if_fail lines in gtk_box_pack
    
    Since the function now returns a value, these checks
    need to be updated.

 gtk/gtkbox.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/gtk/gtkbox.c b/gtk/gtkbox.c
index 7bf8a47..19bb0f9 100644
--- a/gtk/gtkbox.c
+++ b/gtk/gtkbox.c
@@ -1456,9 +1456,9 @@ gtk_box_pack (GtkBox      *box,
   GtkBoxPrivate *private = box->priv;
   GtkBoxChild *child_info;
 
-  g_return_if_fail (GTK_IS_BOX (box));
-  g_return_if_fail (GTK_IS_WIDGET (child));
-  g_return_if_fail (gtk_widget_get_parent (child) == NULL);
+  g_return_val_if_fail (GTK_IS_BOX (box), NULL);
+  g_return_val_if_fail (GTK_IS_WIDGET (child), NULL);
+  g_return_val_if_fail (gtk_widget_get_parent (child) == NULL, NULL);
 
   child_info = g_new (GtkBoxChild, 1);
   child_info->widget = child;