Make some typedefs private instead of protected (these iterators are not designed to be base classes).

include/boost/intrusive/detail/list_iterator.hpp

@@ -34,7 +34,7 @@ namespace intrusive {
 template<class ValueTraits, bool IsConst>
 class list_iterator
 {
-   protected:
+   private:
    typedef iiterator
       <ValueTraits, IsConst, std::bidirectional_iterator_tag> types_t;
 

include/boost/intrusive/detail/slist_iterator.hpp

@@ -36,7 +36,7 @@ namespace intrusive {
 template<class ValueTraits, bool IsConst>
 class slist_iterator
 {
-   protected:
+   private:
    typedef iiterator
       <ValueTraits, IsConst, std::forward_iterator_tag> types_t;