Correct backslash escaping to only operate on non-'path' and 'tool' types.
# /* **************************************************************************
# * *
# * (C) Copyright Paul Mensonides 2002.
# * Distributed under the Boost Software License, Version 1.0. (See
# * accompanying file LICENSE_1_0.txt or copy at
# * http://www.boost.org/LICENSE_1_0.txt)
# * *
# ************************************************************************** */
#
# /* See http://www.boost.org for most recent version. */
#
# ifndef BOOST_PREPROCESSOR_ENUM_HPP
# define BOOST_PREPROCESSOR_ENUM_HPP
#
# include <boost/preprocessor/repetition/enum.hpp>
#
# endif