Revert of Remove the rtc_relative_path GYP variable and similar defines

webrtc/libjingle/xmllite/xmlparser.h

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef WEBRTC_LIBJINGLE_XMLLITE_XMLPARSER_H_
 #define WEBRTC_LIBJINGLE_XMLLITE_XMLPARSER_H_
 
 #include <string>
 
 #include "webrtc/libjingle/xmllite/xmlnsstack.h"
+#ifdef EXPAT_RELATIVE_PATH
 #include "expat.h"
+#else
+#include "third_party/expat/v2_0_1/Source/lib/expat.h"
+#endif  // EXPAT_RELATIVE_PATH
 
 struct XML_ParserStruct;
 typedef struct XML_ParserStruct* XML_Parser;
 
 namespace buzz {
 
 class XmlParseHandler;
 class XmlParseContext;
 class XmlParser;
 
@@ skipping 62 matching lines @@
 
   ParseContext context_;
   XML_Parser expat_;
   XmlParseHandler * pxph_;
   bool sentError_;
 };
 
 }  // namespace buzz
 
 #endif  // WEBRTC_LIBJINGLE_XMLLITE_XMLPARSER_H_