[gtk+] combobox: Add workaround so evolution doesn't crash

[Benjamin Otte <otte src gnome org>]

commit a89c5986177385117ae14c95c38b43b2fe92c896
Author: Benjamin Otte <otte redhat com>
Date:   Mon May 5 15:46:23 2014 +0200

    combobox: Add workaround so evolution doesn't crash
    
    Removing the NULL checks in 7f60cab47d9651ed3ed53b86f1f74de71b55eee0
    caused evolution to crash. It chains up with NULL and that used to work.
    
    This patch should be reverted for GTK 4.0.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=729496

 gtk/gtkcombobox.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkcombobox.c b/gtk/gtkcombobox.c
index 5571604..8176663 100644
--- a/gtk/gtkcombobox.c
+++ b/gtk/gtkcombobox.c
@@ -5505,6 +5505,11 @@ gtk_combo_box_get_preferred_width (GtkWidget *widget,
   gint                   child_min, child_nat;
   GtkBorder              padding;
   gfloat                 arrow_scaling;
+  gint                   dummy;
+
+  /* https://bugzilla.gnome.org/show_bug.cgi?id=729496 */
+  if (natural_size == NULL)
+    natural_size = &dummy;
 
   child = gtk_bin_get_child (GTK_BIN (widget));