Seems I can't "unforget" erroneously forgotten files, so will have to forget them and then re-add them
#ifndef BOOST_SHARED_PTR_HPP_INCLUDED
#define BOOST_SHARED_PTR_HPP_INCLUDED
//
// shared_ptr.hpp
//
// (C) Copyright Greg Colvin and Beman Dawes 1998, 1999.
// Copyright (c) 2001-2008 Peter Dimov
//
// 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/libs/smart_ptr/shared_ptr.htm for documentation.
//
#include <boost/smart_ptr/shared_ptr.hpp>
#endif // #ifndef BOOST_SHARED_PTR_HPP_INCLUDED