Seems I can't "unforget" erroneously forgotten files, so will have to forget them and then re-add them
# /* Copyright (C) 2001
# * Housemarque Oy
# * http://www.housemarque.com
# *
# * 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)
# */
#
# /* Revised by Paul Mensonides (2002) */
#
# /* See http://www.boost.org for most recent version. */
#
# ifndef BOOST_PREPROCESSOR_COMPARISON_HPP
# define BOOST_PREPROCESSOR_COMPARISON_HPP
#
# include <boost/preprocessor/comparison/equal.hpp>
# include <boost/preprocessor/comparison/greater.hpp>
# include <boost/preprocessor/comparison/greater_equal.hpp>
# include <boost/preprocessor/comparison/less.hpp>
# include <boost/preprocessor/comparison/less_equal.hpp>
# include <boost/preprocessor/comparison/not_equal.hpp>
#
# endif