IP_TOS not supported before Windows7

contrib/epee/include/net/abstract_tcp_server2.inl

@@ -160,13 +160,16 @@ PRAGMA_WARNING_DISABLE_VS(4355)
         boost::bind(&connection<t_protocol_handler>::handle_read, self,
           boost::asio::placeholders::error,
           boost::asio::placeholders::bytes_transferred)));
-          
+#if !defined(_WIN32) || !defined(__i686)
+	// not supported before Windows7, too lazy for runtime check
+	// Just exclude for 32bit windows builds
 	//set ToS flag
 	int tos = get_tos_flag();
 	boost::asio::detail::socket_option::integer< IPPROTO_IP, IP_TOS >
 	optionTos( tos );
     socket_.set_option( optionTos );
 	//_dbg1("Set ToS flag to " << tos);
+#endif
 	
 	boost::asio::ip::tcp::no_delay noDelayOption(false);
 	socket_.set_option(noDelayOption);