[boost] Problem in proto library

Hi The addition of macro BOOST_PROTO_EXTENDS_USING_ASSIGN in literal.hpp broke compilation with /clr option in MSVC. The problem is that the macro is used as BOOST_PROTO_EXTENDS_USING_ASSIGN(literal) and literal is a variable modifier for managed C++. Adding a private typedef: typedef literal<T, Domain> literal_t; and replacing the macro parameter with: BOOST_PROTO_EXTENDS_USING_ASSIGN(literal_t) solves the problem for us. Tested with VS2008. Please note that this problem prevents compilation of xpressive and any other library that uses proto with /clr. Thank you for boost and particularly for proto and xpressive :-) Best regards Jorge