fix a few linux compilation warnings

core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
  
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "../../../include/fpdfapi/fpdf_parser.h"
 void CPDF_Object::Release()
 {
     if (m_ObjNum) {
@@ skipping 976 matching lines @@
             if (FXSYS_memcmp32(srcBuf, destBuf, actualSize) != 0) {
                 return FALSE;
             }
             size -= actualSize;
             srcOffset += actualSize;
             destOffset += actualSize;
         }
         return TRUE;
     }
     if (m_GenNum != (FX_DWORD) - 1 || pOther->m_GenNum != (FX_DWORD) - 1) {
+      // TODO(tsepez); unused pFile is probably a bug below.
         IFX_FileRead* pFile = NULL;
         FX_LPBYTE pBuf = NULL;
         FX_DWORD offset = 0;
         if (m_GenNum != (FX_DWORD) - 1) {
             pFile = m_pFile;
             pBuf = pOther->m_pDataBuf;
             offset = m_FileOffset;
         }
         if (pOther->m_GenNum != (FX_DWORD) - 1) {
             pFile = pOther->m_pFile;
@@ skipping 279 matching lines @@
     pObj->m_ObjNum = objnum;
     m_IndirectObjs.SetAt((FX_LPVOID)(FX_UINTPTR)objnum, pObj);
     if (m_LastObjNum < objnum) {
         m_LastObjNum = objnum;
     }
 }
 FX_DWORD CPDF_IndirectObjects::GetLastObjNum() const
 {
     return m_LastObjNum;
 }