Made DestroySignal protected instead of private (as it should have been) so it builds on AIX

widget/src/gtk/nsWidget.h

@@ -187,6 +187,10 @@ class nsWidget : public nsBaseWidget
 
   virtual void OnDestroySignal(GtkWidget* aGtkWidget);
 
+  // Static method used to trampoline to OnDestroySignal
+  static gint DestroySignal(GtkWidget *      aGtkWidget,
+                            nsWidget*        aWidget);
+
 private:
 
   //////////////////////////////////////////////////////////////////
@@ -218,9 +222,6 @@ private:
   static gint RealizeSignal(GtkWidget *      aWidget, 
                             gpointer         aData);
 
-  static gint DestroySignal(GtkWidget *      aGtkWidget,
-                            nsWidget*        aWidget);
-
   //////////////////////////////////////////////////////////////////
   //
   // GTK event support methods