fix attributes warning

src/google/protobuf/compiler/cpp/cpp_message.cc

@@ -1462,9 +1462,9 @@ GenerateClassDefinition(io::Printer* printer) {
   // Some InitDefault and Shutdown are defined as static member functions of
   // TableStruct such that they are also allowed to access private members.
   printer->Print(
-      "friend struct $dllexport_decl$ $file_namespace$::TableStruct;\n",
+      "friend struct $file_namespace$::TableStruct;\n",
       // Vars.
-      "dllexport_decl", options_.dllexport_decl, "file_namespace",
+      "file_namespace",
       FileLevelNamespace(descriptor_->file()->name()));
 
   printer->Outdent();

src/google/protobuf/compiler/plugin.pb.h

@@ -270,7 +270,7 @@ class LIBPROTOC_EXPORT Version : public ::google::protobuf::Message /* @@protoc_
   ::google::protobuf::int32 major_;
   ::google::protobuf::int32 minor_;
   ::google::protobuf::int32 patch_;
-  friend struct LIBPROTOC_EXPORT protobuf_google_2fprotobuf_2fcompiler_2fplugin_2eproto::TableStruct;
+  friend struct protobuf_google_2fprotobuf_2fcompiler_2fplugin_2eproto::TableStruct;
 };
 // -------------------------------------------------------------------
 
@@ -421,7 +421,7 @@ class LIBPROTOC_EXPORT CodeGeneratorRequest : public ::google::protobuf::Message
   ::google::protobuf::RepeatedPtrField< ::google::protobuf::FileDescriptorProto > proto_file_;
   ::google::protobuf::internal::ArenaStringPtr parameter_;
   ::google::protobuf::compiler::Version* compiler_version_;
-  friend struct LIBPROTOC_EXPORT protobuf_google_2fprotobuf_2fcompiler_2fplugin_2eproto::TableStruct;
+  friend struct protobuf_google_2fprotobuf_2fcompiler_2fplugin_2eproto::TableStruct;
 };
 // -------------------------------------------------------------------
 
@@ -560,7 +560,7 @@ class LIBPROTOC_EXPORT CodeGeneratorResponse_File : public ::google::protobuf::M
   ::google::protobuf::internal::ArenaStringPtr name_;
   ::google::protobuf::internal::ArenaStringPtr insertion_point_;
   ::google::protobuf::internal::ArenaStringPtr content_;
-  friend struct LIBPROTOC_EXPORT protobuf_google_2fprotobuf_2fcompiler_2fplugin_2eproto::TableStruct;
+  friend struct protobuf_google_2fprotobuf_2fcompiler_2fplugin_2eproto::TableStruct;
 };
 // -------------------------------------------------------------------
 
@@ -678,7 +678,7 @@ class LIBPROTOC_EXPORT CodeGeneratorResponse : public ::google::protobuf::Messag
   mutable int _cached_size_;
   ::google::protobuf::RepeatedPtrField< ::google::protobuf::compiler::CodeGeneratorResponse_File > file_;
   ::google::protobuf::internal::ArenaStringPtr error_;
-  friend struct LIBPROTOC_EXPORT protobuf_google_2fprotobuf_2fcompiler_2fplugin_2eproto::TableStruct;
+  friend struct protobuf_google_2fprotobuf_2fcompiler_2fplugin_2eproto::TableStruct;
 };
 // ===================================================================