diff --git a/Include/modsupport.h b/Include/modsupport.h
index 9fe8763e5bd..fb196df62dc 100644
--- a/Include/modsupport.h
+++ b/Include/modsupport.h
@@ -52,7 +52,8 @@ extern int vgetargs PROTO((object *, char *, va_list));
 extern object *vmkvalue PROTO((char *, va_list));
 
 extern object *initmodule PROTO((char *, struct methodlist *));
-extern object *initmodule2 PROTO((char *, struct methodlist *, object *));
+extern object *initmodule3 PROTO((char *, struct methodlist *,
+				  char *, object *));
 
 /* The following are obsolete -- use getargs directly! */
 #define getnoarg(v) getargs(v, "")