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/encoding/oid.cpp b/src/encoding/oid.cpp
index d023f82..ae4e12d 100644
--- a/src/encoding/oid.cpp
+++ b/src/encoding/oid.cpp
@@ -5,10 +5,10 @@
  * See COPYING for copyright and distribution information.
  */
 
-#include <stdlib.h>
-#include <sstream>
+#include "common.hpp"
 
-#include "encoding/oid.hpp"
+#include "oid.hpp"
+
 #include <cryptopp/asn.h>
 
 using namespace std;