build: Experimental support to build using precompiled headers

This type of build needs to be explicitly enabled using --with-pch
configure option.

Change-Id: I02dc304187d54c3cf40f1d51b1b11b21f868e225
diff --git a/src/transport/unix-transport.cpp b/src/transport/unix-transport.cpp
index e258f11..4da0502 100644
--- a/src/transport/unix-transport.cpp
+++ b/src/transport/unix-transport.cpp
@@ -5,17 +5,11 @@
  * See COPYING for copyright and distribution information.
  */
 
-#include <stdexcept>
-#include <stdlib.h>
+#include "common.hpp"
 
-#include "face.hpp"
-#include "transport/unix-transport.hpp"
+#include "unix-transport.hpp"
 
-#include <boost/asio.hpp>
-#if NDN_CPP_HAVE_CXX11
-// In the std library, the placeholders are in a different namespace than boost.
-using namespace ndn::func_lib::placeholders;
-#endif
+#include "../face.hpp"
 
 using namespace std;
 typedef boost::asio::local::stream_protocol protocol;