add boost on mac

macx64/include/boost/beast/http/dynamic_body.hpp

@@ -0,0 +1,30 @@
+//
+// Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot 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)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_HTTP_DYNAMIC_BODY_HPP
+#define BOOST_BEAST_HTTP_DYNAMIC_BODY_HPP
+
+#include <boost/beast/core/multi_buffer.hpp>
+#include <boost/beast/http/basic_dynamic_body.hpp>
+
+namespace boost {
+namespace beast {
+namespace http {
+
+/** A dynamic message body represented by a @ref multi_buffer
+
+    Meets the requirements of <em>Body</em>.
+*/
+using dynamic_body = basic_dynamic_body<multi_buffer>;
+
+} // http
+} // beast
+} // boost
+
+#endif