diff --git a/include/config_def.hpp b/include/config_def.hpp
index f31890e..f814655 100644
--- a/include/config_def.hpp
+++ b/include/config_def.hpp
@@ -188,6 +188,8 @@ CONFIG(Difficulty,
 #undef VAR_ENUM
 #undef VAR_ENUM_D
 
+#undef STRUCT_STREAM_OPS
+
 #undef STRUCT
 #undef VAR_STRUCT
 #undef VAR_STRUCT_D