fixing ports bustage

content/xbl/src/nsXBLPrototypeBinding.h

@@ -188,6 +188,9 @@ protected:
   void GetNestedChildren(nsIAtom* aTag, nsIContent* aContent,
                          nsISupportsArray** aList);
 
+  // This should never be called, but is necessary to satisfy nsRefPtr.
+  nsXBLPrototypeBinding() { NS_NOTREACHED("nsXBLPrototypeBinding default ctor"); }
+
 protected:
   // Internal helper class for managing our IID table.
   class nsIIDKey : public nsHashKey {