[boost] [serialization][1.41] export.hpp should #include extended_type_info.hpp

Hi everyone. Header file <boost/serialization/export.hpp> has a dependency to <boost/serialization/extended_type_info.hpp>, because it defines the macro BOOST_CLASS_EXPORT_KEY2 which specializes the class template guid_defined<> which, in turn, is defined in extended_type_info.hpp. Perhaps export.hpp should #include extended_type_info.hpp? Regards, Marco