tools: fix compilation with Boost 1.67
Change-Id: I0f4bae23f26eca07044990ce6dd01da750cfb569
Refs: #4584
diff --git a/src/net/asio-fwd.hpp b/src/net/asio-fwd.hpp
index bda6b83..fb80ee5 100644
--- a/src/net/asio-fwd.hpp
+++ b/src/net/asio-fwd.hpp
@@ -1,6 +1,6 @@
/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
- * Copyright (c) 2013-2017 Regents of the University of California.
+ * Copyright (c) 2013-2018 Regents of the University of California.
*
* This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
*
@@ -24,24 +24,17 @@
#include <boost/version.hpp>
+namespace boost {
+namespace asio {
+
#if BOOST_VERSION >= 106600
-
-#include <boost/asio/ts/netfwd.hpp>
-
-namespace boost {
-namespace asio {
+class io_context;
using io_service = io_context;
-} // namespace asio
-} // namespace boost
-
#else
-
-namespace boost {
-namespace asio {
class io_service;
+#endif // BOOST_VERSION >= 106600
+
} // namespace asio
} // namespace boost
-#endif // BOOST_VERSION >= 106600
-
#endif // NDN_NET_ASIO_FWD_HPP