Get VS 2015 to use const int definitions

VC++ up to VS 2015 RTM does not require explicit storage allocation for
static const integers declared in classes. VS 2015 Update 1 requires
these storage definitions in some cases. It's unclear exactly what
cases - simple tests work with and without the explicit storage
allocation.

Many previous versions of VC++ have theoretically *allowed* a
definition to supply storage, but tests on VC++ 2013 show that this
doesn't actually work correctly - it leads to duplicate definition
errors in Chromium. So, the change is scoped to VS 2015 only.

This change also updates the generated files to match the new generator.

TL;DR - this change is necessary in order for Chromium to build with
VS 2015 Update 1.

7 files changed, 72 insertions, 70 deletions

diff --git a/src/google/protobuf/compiler/cpp/cpp_enum.cc b/src/google/protobuf/compiler/cpp/cpp_enum.cc
index de4d7cc7..1a11bce8 100644
--- a/src/google/protobuf/compiler/cpp/cpp_enum.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_enum.cc
@@ -278,9 +278,9 @@ void EnumGenerator::GenerateMethods(io::Printer* printer) {
   if (descriptor_->containing_type() != NULL) {
     // We need to "define" the static constants which were declared in the
     // header, to give the linker a place to put them.  Or at least the C++
-    // standard says we have to.  MSVC actually insists tha we do _not_ define
-    // them again in the .cc file.
-    printer->Print("#ifndef _MSC_VER\n");
+    // standard says we have to.  MSVC actually insists that we do _not_ define
+    // them again in the .cc file, prior to VC++ 2015.
+    printer->Print("#if !defined(_MSC_VER) || _MSC_VER >= 1900\n");
 
     vars["parent"] = ClassName(descriptor_->containing_type(), false);
     vars["nested_name"] = descriptor_->name();
@@ -297,7 +297,7 @@ void EnumGenerator::GenerateMethods(io::Printer* printer) {
         "const int $parent$::$nested_name$_ARRAYSIZE;\n");
     }
 
-    printer->Print("#endif  // _MSC_VER\n");
+    printer->Print("#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900\n");
   }
 }
 
diff --git a/src/google/protobuf/compiler/cpp/cpp_extension.cc b/src/google/protobuf/compiler/cpp/cpp_extension.cc
index 468ca484..c42f1627 100644
--- a/src/google/protobuf/compiler/cpp/cpp_extension.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_extension.cc
@@ -155,7 +155,7 @@ void ExtensionGenerator::GenerateDefinition(io::Printer* printer) {
   // Likewise, class members need to declare the field constant variable.
   if (descriptor_->extension_scope() != NULL) {
     printer->Print(vars,
-      "#ifndef _MSC_VER\n"
+      "#if !defined(_MSC_VER) || _MSC_VER >= 1900\n"
       "const int $scope$$constant_name$;\n"
       "#endif\n");
   }
diff --git a/src/google/protobuf/compiler/cpp/cpp_message.cc b/src/google/protobuf/compiler/cpp/cpp_message.cc
index 8cc8c7ba..8c0bfab7 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_message.cc
@@ -1807,7 +1807,7 @@ GenerateClassMethods(io::Printer* printer) {
   }
 
   // Generate field number constants.
-  printer->Print("#ifndef _MSC_VER\n");
+  printer->Print("#if !defined(_MSC_VER) || _MSC_VER >= 1900\n");
   for (int i = 0; i < descriptor_->field_count(); i++) {
     const FieldDescriptor *field = descriptor_->field(i);
     printer->Print(
@@ -1816,7 +1816,7 @@ GenerateClassMethods(io::Printer* printer) {
       "constant_name", FieldConstantName(field));
   }
   printer->Print(
-    "#endif  // !_MSC_VER\n"
+    "#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900\n"
     "\n");
 
   // Define extension identifiers.
diff --git a/src/google/protobuf/compiler/plugin.pb.cc b/src/google/protobuf/compiler/plugin.pb.cc
index 0792d875..266c2975 100644
--- a/src/google/protobuf/compiler/plugin.pb.cc
+++ b/src/google/protobuf/compiler/plugin.pb.cc
@@ -172,11 +172,11 @@ static void MergeFromFail(int line) {
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int CodeGeneratorRequest::kFileToGenerateFieldNumber;
 const int CodeGeneratorRequest::kParameterFieldNumber;
 const int CodeGeneratorRequest::kProtoFileFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 CodeGeneratorRequest::CodeGeneratorRequest()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -656,11 +656,11 @@ CodeGeneratorRequest::proto_file() const {
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int CodeGeneratorResponse_File::kNameFieldNumber;
 const int CodeGeneratorResponse_File::kInsertionPointFieldNumber;
 const int CodeGeneratorResponse_File::kContentFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 CodeGeneratorResponse_File::CodeGeneratorResponse_File()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -1021,10 +1021,10 @@ void CodeGeneratorResponse_File::InternalSwap(CodeGeneratorResponse_File* other)
 
 // -------------------------------------------------------------------
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int CodeGeneratorResponse::kErrorFieldNumber;
 const int CodeGeneratorResponse::kFileFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 CodeGeneratorResponse::CodeGeneratorResponse()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
diff --git a/src/google/protobuf/descriptor.cc b/src/google/protobuf/descriptor.cc
index b40fe95a..9a1c6fe8 100644
--- a/src/google/protobuf/descriptor.cc
+++ b/src/google/protobuf/descriptor.cc
@@ -156,7 +156,7 @@ const char* FileDescriptor::SyntaxName(FileDescriptor::Syntax syntax) {
 
 static const char * const kNonLinkedWeakMessageReplacementName = "google.protobuf.Empty";
 
-#ifndef _MSC_VER  // MSVC doesn't need these and won't even accept them.
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int FieldDescriptor::kMaxNumber;
 const int FieldDescriptor::kFirstReservedNumber;
 const int FieldDescriptor::kLastReservedNumber;
diff --git a/src/google/protobuf/descriptor.pb.cc b/src/google/protobuf/descriptor.pb.cc
index 9c817122..ad53c03f 100644
--- a/src/google/protobuf/descriptor.pb.cc
+++ b/src/google/protobuf/descriptor.pb.cc
@@ -828,9 +828,9 @@ static void MergeFromFail(int line) {
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int FileDescriptorSet::kFileFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 FileDescriptorSet::FileDescriptorSet()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -1095,7 +1095,7 @@ FileDescriptorSet::file() const {
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int FileDescriptorProto::kNameFieldNumber;
 const int FileDescriptorProto::kPackageFieldNumber;
 const int FileDescriptorProto::kDependencyFieldNumber;
@@ -1108,7 +1108,7 @@ const int FileDescriptorProto::kExtensionFieldNumber;
 const int FileDescriptorProto::kOptionsFieldNumber;
 const int FileDescriptorProto::kSourceCodeInfoFieldNumber;
 const int FileDescriptorProto::kSyntaxFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 FileDescriptorProto::FileDescriptorProto()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -2349,10 +2349,10 @@ void FileDescriptorProto::clear_syntax() {
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int DescriptorProto_ExtensionRange::kStartFieldNumber;
 const int DescriptorProto_ExtensionRange::kEndFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 DescriptorProto_ExtensionRange::DescriptorProto_ExtensionRange()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -2632,10 +2632,10 @@ void DescriptorProto_ExtensionRange::InternalSwap(DescriptorProto_ExtensionRange
 
 // -------------------------------------------------------------------
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int DescriptorProto_ReservedRange::kStartFieldNumber;
 const int DescriptorProto_ReservedRange::kEndFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 DescriptorProto_ReservedRange::DescriptorProto_ReservedRange()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -2915,7 +2915,7 @@ void DescriptorProto_ReservedRange::InternalSwap(DescriptorProto_ReservedRange*
 
 // -------------------------------------------------------------------
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int DescriptorProto::kNameFieldNumber;
 const int DescriptorProto::kFieldFieldNumber;
 const int DescriptorProto::kExtensionFieldNumber;
@@ -2926,7 +2926,7 @@ const int DescriptorProto::kOneofDeclFieldNumber;
 const int DescriptorProto::kOptionsFieldNumber;
 const int DescriptorProto::kReservedRangeFieldNumber;
 const int DescriptorProto::kReservedNameFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 DescriptorProto::DescriptorProto()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -4056,7 +4056,7 @@ bool FieldDescriptorProto_Type_IsValid(int value) {
   }
 }
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const FieldDescriptorProto_Type FieldDescriptorProto::TYPE_DOUBLE;
 const FieldDescriptorProto_Type FieldDescriptorProto::TYPE_FLOAT;
 const FieldDescriptorProto_Type FieldDescriptorProto::TYPE_INT64;
@@ -4078,7 +4078,7 @@ const FieldDescriptorProto_Type FieldDescriptorProto::TYPE_SINT64;
 const FieldDescriptorProto_Type FieldDescriptorProto::Type_MIN;
 const FieldDescriptorProto_Type FieldDescriptorProto::Type_MAX;
 const int FieldDescriptorProto::Type_ARRAYSIZE;
-#endif  // _MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 const ::google::protobuf::EnumDescriptor* FieldDescriptorProto_Label_descriptor() {
   protobuf_AssignDescriptorsOnce();
   return FieldDescriptorProto_Label_descriptor_;
@@ -4094,15 +4094,15 @@ bool FieldDescriptorProto_Label_IsValid(int value) {
   }
 }
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const FieldDescriptorProto_Label FieldDescriptorProto::LABEL_OPTIONAL;
 const FieldDescriptorProto_Label FieldDescriptorProto::LABEL_REQUIRED;
 const FieldDescriptorProto_Label FieldDescriptorProto::LABEL_REPEATED;
 const FieldDescriptorProto_Label FieldDescriptorProto::Label_MIN;
 const FieldDescriptorProto_Label FieldDescriptorProto::Label_MAX;
 const int FieldDescriptorProto::Label_ARRAYSIZE;
-#endif  // _MSC_VER
-#ifndef _MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int FieldDescriptorProto::kNameFieldNumber;
 const int FieldDescriptorProto::kNumberFieldNumber;
 const int FieldDescriptorProto::kLabelFieldNumber;
@@ -4113,7 +4113,7 @@ const int FieldDescriptorProto::kDefaultValueFieldNumber;
 const int FieldDescriptorProto::kOneofIndexFieldNumber;
 const int FieldDescriptorProto::kJsonNameFieldNumber;
 const int FieldDescriptorProto::kOptionsFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 FieldDescriptorProto::FieldDescriptorProto()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -5210,9 +5210,9 @@ void FieldDescriptorProto::set_allocated_options(::google::protobuf::FieldOption
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int OneofDescriptorProto::kNameFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 OneofDescriptorProto::OneofDescriptorProto()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -5516,11 +5516,11 @@ void OneofDescriptorProto::clear_name() {
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int EnumDescriptorProto::kNameFieldNumber;
 const int EnumDescriptorProto::kValueFieldNumber;
 const int EnumDescriptorProto::kOptionsFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 EnumDescriptorProto::EnumDescriptorProto()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -5989,11 +5989,11 @@ void EnumDescriptorProto::set_allocated_options(::google::protobuf::EnumOptions*
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int EnumValueDescriptorProto::kNameFieldNumber;
 const int EnumValueDescriptorProto::kNumberFieldNumber;
 const int EnumValueDescriptorProto::kOptionsFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 EnumValueDescriptorProto::EnumValueDescriptorProto()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -6452,11 +6452,11 @@ void EnumValueDescriptorProto::set_allocated_options(::google::protobuf::EnumVal
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int ServiceDescriptorProto::kNameFieldNumber;
 const int ServiceDescriptorProto::kMethodFieldNumber;
 const int ServiceDescriptorProto::kOptionsFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 ServiceDescriptorProto::ServiceDescriptorProto()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -6925,14 +6925,14 @@ void ServiceDescriptorProto::set_allocated_options(::google::protobuf::ServiceOp
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int MethodDescriptorProto::kNameFieldNumber;
 const int MethodDescriptorProto::kInputTypeFieldNumber;
 const int MethodDescriptorProto::kOutputTypeFieldNumber;
 const int MethodDescriptorProto::kOptionsFieldNumber;
 const int MethodDescriptorProto::kClientStreamingFieldNumber;
 const int MethodDescriptorProto::kServerStreamingFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 MethodDescriptorProto::MethodDescriptorProto()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -7691,15 +7691,15 @@ bool FileOptions_OptimizeMode_IsValid(int value) {
   }
 }
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const FileOptions_OptimizeMode FileOptions::SPEED;
 const FileOptions_OptimizeMode FileOptions::CODE_SIZE;
 const FileOptions_OptimizeMode FileOptions::LITE_RUNTIME;
 const FileOptions_OptimizeMode FileOptions::OptimizeMode_MIN;
 const FileOptions_OptimizeMode FileOptions::OptimizeMode_MAX;
 const int FileOptions::OptimizeMode_ARRAYSIZE;
-#endif  // _MSC_VER
-#ifndef _MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int FileOptions::kJavaPackageFieldNumber;
 const int FileOptions::kJavaOuterClassnameFieldNumber;
 const int FileOptions::kJavaMultipleFilesFieldNumber;
@@ -7716,7 +7716,7 @@ const int FileOptions::kObjcClassPrefixFieldNumber;
 const int FileOptions::kCsharpNamespaceFieldNumber;
 const int FileOptions::kJavananoUseDeprecatedPackageFieldNumber;
 const int FileOptions::kUninterpretedOptionFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 FileOptions::FileOptions()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -9167,13 +9167,13 @@ FileOptions::uninterpreted_option() const {
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int MessageOptions::kMessageSetWireFormatFieldNumber;
 const int MessageOptions::kNoStandardDescriptorAccessorFieldNumber;
 const int MessageOptions::kDeprecatedFieldNumber;
 const int MessageOptions::kMapEntryFieldNumber;
 const int MessageOptions::kUninterpretedOptionFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 MessageOptions::MessageOptions()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -9725,14 +9725,14 @@ bool FieldOptions_CType_IsValid(int value) {
   }
 }
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const FieldOptions_CType FieldOptions::STRING;
 const FieldOptions_CType FieldOptions::CORD;
 const FieldOptions_CType FieldOptions::STRING_PIECE;
 const FieldOptions_CType FieldOptions::CType_MIN;
 const FieldOptions_CType FieldOptions::CType_MAX;
 const int FieldOptions::CType_ARRAYSIZE;
-#endif  // _MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 const ::google::protobuf::EnumDescriptor* FieldOptions_JSType_descriptor() {
   protobuf_AssignDescriptorsOnce();
   return FieldOptions_JSType_descriptor_;
@@ -9748,15 +9748,15 @@ bool FieldOptions_JSType_IsValid(int value) {
   }
 }
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const FieldOptions_JSType FieldOptions::JS_NORMAL;
 const FieldOptions_JSType FieldOptions::JS_STRING;
 const FieldOptions_JSType FieldOptions::JS_NUMBER;
 const FieldOptions_JSType FieldOptions::JSType_MIN;
 const FieldOptions_JSType FieldOptions::JSType_MAX;
 const int FieldOptions::JSType_ARRAYSIZE;
-#endif  // _MSC_VER
-#ifndef _MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int FieldOptions::kCtypeFieldNumber;
 const int FieldOptions::kPackedFieldNumber;
 const int FieldOptions::kJstypeFieldNumber;
@@ -9764,7 +9764,7 @@ const int FieldOptions::kLazyFieldNumber;
 const int FieldOptions::kDeprecatedFieldNumber;
 const int FieldOptions::kWeakFieldNumber;
 const int FieldOptions::kUninterpretedOptionFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 FieldOptions::FieldOptions()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -10440,11 +10440,11 @@ FieldOptions::uninterpreted_option() const {
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int EnumOptions::kAllowAliasFieldNumber;
 const int EnumOptions::kDeprecatedFieldNumber;
 const int EnumOptions::kUninterpretedOptionFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 EnumOptions::EnumOptions()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -10863,10 +10863,10 @@ EnumOptions::uninterpreted_option() const {
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int EnumValueOptions::kDeprecatedFieldNumber;
 const int EnumValueOptions::kUninterpretedOptionFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 EnumValueOptions::EnumValueOptions()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -11212,10 +11212,10 @@ EnumValueOptions::uninterpreted_option() const {
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int ServiceOptions::kDeprecatedFieldNumber;
 const int ServiceOptions::kUninterpretedOptionFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 ServiceOptions::ServiceOptions()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -11561,10 +11561,10 @@ ServiceOptions::uninterpreted_option() const {
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int MethodOptions::kDeprecatedFieldNumber;
 const int MethodOptions::kUninterpretedOptionFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 MethodOptions::MethodOptions()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -11910,10 +11910,10 @@ MethodOptions::uninterpreted_option() const {
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int UninterpretedOption_NamePart::kNamePartFieldNumber;
 const int UninterpretedOption_NamePart::kIsExtensionFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 UninterpretedOption_NamePart::UninterpretedOption_NamePart()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -12216,7 +12216,7 @@ void UninterpretedOption_NamePart::InternalSwap(UninterpretedOption_NamePart* ot
 
 // -------------------------------------------------------------------
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int UninterpretedOption::kNameFieldNumber;
 const int UninterpretedOption::kIdentifierValueFieldNumber;
 const int UninterpretedOption::kPositiveIntValueFieldNumber;
@@ -12224,7 +12224,7 @@ const int UninterpretedOption::kNegativeIntValueFieldNumber;
 const int UninterpretedOption::kDoubleValueFieldNumber;
 const int UninterpretedOption::kStringValueFieldNumber;
 const int UninterpretedOption::kAggregateValueFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 UninterpretedOption::UninterpretedOption()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -13083,13 +13083,13 @@ void UninterpretedOption::clear_aggregate_value() {
 
 // ===================================================================
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int SourceCodeInfo_Location::kPathFieldNumber;
 const int SourceCodeInfo_Location::kSpanFieldNumber;
 const int SourceCodeInfo_Location::kLeadingCommentsFieldNumber;
 const int SourceCodeInfo_Location::kTrailingCommentsFieldNumber;
 const int SourceCodeInfo_Location::kLeadingDetachedCommentsFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 SourceCodeInfo_Location::SourceCodeInfo_Location()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
@@ -13568,9 +13568,9 @@ void SourceCodeInfo_Location::InternalSwap(SourceCodeInfo_Location* other) {
 
 // -------------------------------------------------------------------
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
 const int SourceCodeInfo::kLocationFieldNumber;
-#endif  // !_MSC_VER
+#endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 SourceCodeInfo::SourceCodeInfo()
   : ::google::protobuf::Message(), _internal_metadata_(NULL) {
diff --git a/src/google/protobuf/wire_format_lite.cc b/src/google/protobuf/wire_format_lite.cc
index 847e3500..7f1093c8 100644
--- a/src/google/protobuf/wire_format_lite.cc
+++ b/src/google/protobuf/wire_format_lite.cc
@@ -49,8 +49,10 @@ namespace google {
 namespace protobuf {
 namespace internal {
 
-#ifndef _MSC_VER    // MSVC doesn't like definitions of inline constants, GCC
-                    // requires them.
+
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
+// Old version of MSVC doesn't like definitions of inline constants, GCC
+// requires them.
 const int WireFormatLite::kMessageSetItemStartTag;
 const int WireFormatLite::kMessageSetItemEndTag;
 const int WireFormatLite::kMessageSetTypeIdTag;