add boost on mac

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

@@ -0,0 +1,37 @@
+//
+// 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_FILE_BODY_HPP
+#define BOOST_BEAST_HTTP_FILE_BODY_HPP
+
+#include <boost/beast/core/file.hpp>
+#include <boost/beast/http/basic_file_body.hpp>
+#include <boost/assert.hpp>
+#include <boost/optional.hpp>
+#include <algorithm>
+#include <cstdio>
+#include <cstdint>
+#include <utility>
+
+namespace boost {
+namespace beast {
+namespace http {
+
+/// A message body represented by a file on the filesystem.
+using file_body = basic_file_body<file>;
+
+} // http
+} // beast
+} // boost
+
+#ifndef BOOST_BEAST_NO_FILE_BODY_WIN32
+#include <boost/beast/http/impl/file_body_win32.hpp>
+#endif
+
+#endif