add boost on mac

macx64/include/boost/asio/impl/execution_context.ipp

@@ -0,0 +1,84 @@
+//
+// impl/execution_context.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff 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)
+//
+
+#ifndef BOOST_ASIO_IMPL_EXECUTION_CONTEXT_IPP
+#define BOOST_ASIO_IMPL_EXECUTION_CONTEXT_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <boost/asio/detail/config.hpp>
+#include <boost/asio/execution_context.hpp>
+#include <boost/asio/detail/service_registry.hpp>
+
+#include <boost/asio/detail/push_options.hpp>
+
+namespace boost {
+namespace asio {
+
+execution_context::execution_context()
+  : service_registry_(new boost::asio::detail::service_registry(*this))
+{
+}
+
+execution_context::~execution_context()
+{
+  shutdown();
+  destroy();
+  delete service_registry_;
+}
+
+void execution_context::shutdown()
+{
+  service_registry_->shutdown_services();
+}
+
+void execution_context::destroy()
+{
+  service_registry_->destroy_services();
+}
+
+void execution_context::notify_fork(
+    boost::asio::execution_context::fork_event event)
+{
+  service_registry_->notify_fork(event);
+}
+
+execution_context::service::service(execution_context& owner)
+  : owner_(owner),
+    next_(0)
+{
+}
+
+execution_context::service::~service()
+{
+}
+
+void execution_context::service::notify_fork(execution_context::fork_event)
+{
+}
+
+service_already_exists::service_already_exists()
+  : std::logic_error("Service already exists.")
+{
+}
+
+invalid_service_owner::invalid_service_owner()
+  : std::logic_error("Invalid service owner.")
+{
+}
+
+} // namespace asio
+} // namespace boost
+
+#include <boost/asio/detail/pop_options.hpp>
+
+#endif // BOOST_ASIO_IMPL_EXECUTION_CONTEXT_IPP