Fix four annoying warnings:

core/src/fpdfapi/fpdf_page/fpdf_page_func.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 <limits.h>
 
 #include "../../../include/fpdfapi/fpdf_page.h"
 #include "../../../include/fpdfapi/fpdf_module.h"
@@ skipping 55 matching lines @@
     for (int i = 0; i < size; i ++) {
         if (m_Operators[i] == (FX_LPVOID)PSOP_PROC) {
             delete (CPDF_PSProc*)m_Operators[i + 1];
             i ++;
         } else if (m_Operators[i] == (FX_LPVOID)PSOP_CONST) {
             FX_Free((FX_FLOAT*)m_Operators[i + 1]);
             i ++;
         }
     }
 }
+#if _FXM_PLATFORM_ == _FX_PLATFORM_WINDOWS_

[Lei Zhang, 2015/05/20 21:43:16]

Hans: do you know if Clang for Windows will support this #pragma? If not, maybe
this should check for something like MSC_VER?

[hans, 2015/05/20 21:53:07]

It doesn't support it currently, and I don't see it getting support anytime
soon.

Note that clang on Windows also sneakily defines _MSC_VER, so you'd probably
want to check that __clang__ is not defined too.

On a higher level, why is this pragma needed? If the code relies on
optimizations being disabled to function properly, that sounds extremely dodgy.

[Tom Sepez, 2015/05/21 00:07:23]

Remove it and HFTB.

[Lei Zhang, 2015/05/21 00:14:08]

Do you want to ask Jun about this? He may know why this was added in the first
place. AFAICT, this has been in the old internal SVN repo since the beginning.

 #pragma optimize( "", off )
+#endif
 FX_BOOL CPDF_PSProc::Execute(CPDF_PSEngine* pEngine)
 {
     int size = m_Operators.GetSize();
     for (int i = 0; i < size; i ++) {
         PDF_PSOP op = (PDF_PSOP)(FX_UINTPTR)m_Operators[i];
         if (op == PSOP_PROC) {
             i ++;
         } else if (op == PSOP_CONST) {
             pEngine->Push(*(FX_FLOAT*)m_Operators[i + 1]);
             i ++;
@@ skipping 13 matching lines @@
                 ((CPDF_PSProc*)m_Operators[i - 3])->Execute(pEngine);
             } else {
                 ((CPDF_PSProc*)m_Operators[i - 1])->Execute(pEngine);
             }
         } else {
             pEngine->DoOperator(op);
         }
     }
     return TRUE;
 }
+#if _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_
 #pragma optimize( "", on )
+#endif
 CPDF_PSEngine::CPDF_PSEngine()
 {
     m_StackCount = 0;
 }
 CPDF_PSEngine::~CPDF_PSEngine()
 {
 }
 void CPDF_PSEngine::Push(FX_FLOAT v)
 {
     if (m_StackCount == 100) {
@@ skipping 777 matching lines @@
         for (int i = 0; i < m_nOutputs; i ++) {
             if (results[i] < m_pRanges[i * 2]) {
                 results[i] = m_pRanges[i * 2];
             } else if (results[i] > m_pRanges[i * 2 + 1]) {
                 results[i] = m_pRanges[i * 2 + 1];
             }
         }
     }
     return TRUE;
 }