src/Pure/ProofGeneral/proof_general_emacs.ML

         (Output.add_mode Symbol.xsymbolsN Symbol.output Output.default_escape;
          Output.add_mode ProofGeneralPgip.proof_general_emacsN
           Output.default_output Output.default_escape;
          Markup.add_mode ProofGeneralPgip.proof_general_emacsN YXML.output_markup;
          setup_messages ();
-         ProofGeneralPgip.pgip_channel_emacs (! Output.Private_Hooks.urgent_message_fn);
+         ProofGeneralPgip.init_pgip_session_id ();
          setup_thy_loader ();
          setup_present_hook ();
          initialized := true);
        sync_thy_loader ();
        Unsynchronized.change print_mode (update (op =) ProofGeneralPgip.proof_general_emacsN);