src/Pure/Tools/build.scala

       "v" -> (_ => verbose = true),
       "x:" -> (arg => exclude_sessions = exclude_sessions ::: List(arg)))
 
     val sessions = getopts(args)
 
-    val progress = new Console_Progress(verbose)
+    val progress = new Console_Progress(verbose = verbose)
 
     if (verbose) {
       progress.echo(
         Library.trim_line(
           Isabelle_System.bash(