support for boost::tuples

[SVN r35350]

include/boost/fusion/support/is_sequence.hpp

@@ -19,6 +19,7 @@ namespace boost { namespace fusion
 {
     // Special tags:
     struct non_fusion_tag;
+    struct boost_tuple_tag; // boost::tuples::tuple tag
     struct array_tag; // boost::array tag
     struct mpl_sequence_tag; // mpl sequence tag
     struct std_pair_tag; // std::pair tag
@@ -39,6 +40,9 @@ namespace boost { namespace fusion
             struct apply : mpl::false_ {};
         };
 
+        template <>
+        struct is_sequence_impl<boost_tuple_tag>;
+
         template <>
         struct is_sequence_impl<array_tag>;