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

Index: protoc-c/c_enum_field.h
--- protoc-c/c_enum_field.h.orig
+++ protoc-c/c_enum_field.h
@@ -85,8 +85,6 @@ class EnumFieldGenerator : public FieldGenerator {
 
  private:
   std::map<std::string, std::string> variables_;
-
-  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(EnumFieldGenerator);
 };