diff --git a/src/os_riscos.c b/src/os_riscos.c
index 39a03cc..cc52d85 100644
--- a/src/os_riscos.c
+++ b/src/os_riscos.c
@@ -1245,7 +1245,7 @@
 	;
     type_string[i] = 0;
 
-    set_string_option_direct("osfiletype", -1, type_string, OPT_FREE);
+    set_string_option_direct("osfiletype", -1, type_string, OPT_FREE, 0);
     return;
 }