add boost on mac

macx64/include/boost/log/utility/value_ref_fwd.hpp

@@ -0,0 +1,38 @@
+/*
+ *          Copyright Andrey Semashev 2007 - 2015.
+ * 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)
+ */
+/*!
+ * \file   value_ref_fwd.hpp
+ * \author Andrey Semashev
+ * \date   27.07.2012
+ *
+ * The header contains forward declaration of a value reference wrapper.
+ */
+
+#ifndef BOOST_LOG_UTILITY_VALUE_REF_FWD_HPP_INCLUDED_
+#define BOOST_LOG_UTILITY_VALUE_REF_FWD_HPP_INCLUDED_
+
+#include <boost/log/detail/config.hpp>
+
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#pragma once
+#endif
+
+namespace boost {
+
+BOOST_LOG_OPEN_NAMESPACE
+
+/*!
+ * \brief Reference wrapper for a stored attribute value.
+ */
+template< typename T, typename TagT = void >
+class value_ref;
+
+BOOST_LOG_CLOSE_NAMESPACE // namespace log
+
+} // namespace boost
+
+#endif // BOOST_LOG_UTILITY_VALUE_REF_FWD_HPP_INCLUDED_