src/Pure/System/getopts.scala

--- a/src/Pure/System/getopts.scala	Sun Sep 12 22:31:51 2021 +0200
+++ b/src/Pure/System/getopts.scala	Mon Sep 13 11:52:32 2021 +0200
@@ -33,7 +33,7 @@
   def usage(): Nothing =
   {
     Output.writeln(usage_text, stdout = true)
-    sys.exit(1)
+    sys.exit(Process_Result.RC.error)
   }
 
   private def is_option(opt: Char): Boolean = options.isDefinedAt(opt)