Resolve all but two VC++ build warnings in pdfium.

build/standalone.gypi

 # 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.
 
 # Definitions to be used when building stand-alone PDFium binaries.
 
 {
   'variables': {
     'component%': 'static_library',
     'clang%': 0,
@@ skipping 147 matching lines @@
     ],
     'ldflags': [
       '-pthread',
     ],
     'msvs_cygwin_dirs': ['<(DEPTH)/v8/third_party/cygwin'],
     'msvs_configuration_attributes': {
       'OutputDirectory': '<(DEPTH)\\build\\$(ConfigurationName)',
       'IntermediateDirectory': '$(OutDir)\\obj\\$(ProjectName)',
       'CharacterSet': '1',
     },
+    'msvs_disabled_warnings': [4800, 4996],
     'msvs_settings': {
       'VCCLCompilerTool': {
         'MinimalRebuild': 'false',
         'BufferSecurityCheck': 'true',
         'EnableFunctionLevelLinking': 'true',
         'RuntimeTypeInfo': 'false',
         'WarningLevel': '3',
-        'WarnAsError': 'false',
         'DebugInformationFormat': '3',
         'Detect64BitPortabilityProblems': 'false',
         'conditions': [
           [ 'msvs_multi_core_compile', {
             'AdditionalOptions': ['/MP'],
           }],
           ['component=="shared_library"', {
             'ExceptionHandling': '1',  # /EHsc
           }, {
             'ExceptionHandling': '0',
           }],
+          ['target_arch=="x64"', {
+            # 64-bit warnings need to be resolved.
+            # https://code.google.com/p/pdfium/issues/detail?id=101
+            'WarnAsError': 'false',
+          }, {
+            'WarnAsError': 'true',
+          }],
         ],
       },
       'VCLibrarianTool': {
         'AdditionalOptions': ['/ignore:4221'],
       },
       'VCLinkerTool': {
         'GenerateDebugInformation': 'true',
         'LinkIncremental': '1',
         # SubSystem values:
         #   0 == not set
@@ skipping 59 matching lines @@
           }],
         ],  # target_conditions
       },  # target_defaults
     }],  # OS=="mac"
   ],
   'xcode_settings': {
     # See comment in Chromium's common.gypi for why this is needed.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   }
 }