--- a/incubator/mod_oorexx/make_mod_oorexx.rex
+++ b/incubator/mod_oorexx/make_mod_oorexx.rex
@@ -41,7 +41,7 @@
 
 
 /* find out the operating system */
-use arg cmdline
+use arg cmdline = ''
 parse source source_str
 parse var source_str os .
 if substr(os, 1, 7) = 'Windows' then os = 'WINDOWS'