updated boost on windows

winx64/include/boost/asio/error.hpp

@@ -2,7 +2,7 @@
 // error.hpp
 // ~~~~~~~~~
 //
-// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// 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)
@@ -327,6 +327,22 @@ inline boost::system::error_code make_error_code(misc_errors e)
 }
 
 } // namespace error
+namespace stream_errc {
+  // Simulates the proposed stream_errc scoped enum.
+  using error::eof;
+  using error::not_found;
+} // namespace stream_errc
+namespace socket_errc {
+  // Simulates the proposed socket_errc scoped enum.
+  using error::already_open;
+  using error::not_found;
+} // namespace socket_errc
+namespace resolver_errc {
+  // Simulates the proposed resolver_errc scoped enum.
+  using error::host_not_found;
+  const error::netdb_errors try_again = error::host_not_found_try_again;
+  using error::service_not_found;
+} // namespace resolver_errc
 } // namespace asio
 } // namespace boost