diff --git a/m_option.h b/m_option.h
index 9254f4a423..0c528ceba0 100644
--- a/m_option.h
+++ b/m_option.h
@@ -5,7 +5,7 @@
 
 typedef struct m_option_type m_option_type_t;
 typedef struct m_option m_option_t;
-struct m_struct;
+struct m_struct_st;
 
 ///////////////////////////// Options types declarations ////////////////////////////