https://github.com/protobuf-c/protobuf-c/pull/673

Index: protoc-c/c_message.h
--- protoc-c/c_message.h.orig
+++ protoc-c/c_message.h
@@ -136,8 +136,6 @@ class MessageGenerator {
   std::unique_ptr<std::unique_ptr<MessageGenerator>[]> nested_generators_;
   std::unique_ptr<std::unique_ptr<EnumGenerator>[]> enum_generators_;
   std::unique_ptr<std::unique_ptr<ExtensionGenerator>[]> extension_generators_;
-
-  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(MessageGenerator);
 };
 
 }  // namespace c