src/Pure/Tools/build.scala

           process.result(
             progress_stdout = (line: String) =>
               line match {
                 case Loading_Theory_Marker(theory) =>
                   progress.theory(Progress.Theory(theory, session = name))
-                case Markup.Export.Marker((args, path)) =>
+                case Protocol.Export.Marker((args, path)) =>
                   val body =
                     try { Bytes.read(path) }
                     catch {
                       case ERROR(msg) =>
                         error("Failed to read export " + quote(args.compound_name) + "\n" + msg)