use setmp_noncritical for PGIP, which is presumably sequential (PG clone);

--- a/src/Pure/ProofGeneral/proof_general_pgip.ML	Sun Sep 05 23:26:16 2010 +0200
+++ b/src/Pure/ProofGeneral/proof_general_pgip.ML	Sun Sep 05 23:31:12 2010 +0200
@@ -1044,7 +1044,7 @@
    This works for preferences but not generally guaranteed
    because we haven't done full setup here (e.g., no pgml mode)  *)
 fun process_pgip_emacs str =
-     setmp_CRITICAL output_xml_fn (!pgip_output_channel) process_pgip_plain str
+     setmp_noncritical output_xml_fn (!pgip_output_channel) process_pgip_plain str
 
 end