Future.shutdown before loading sequentially -- workaround scheduler deadlock;

--- a/src/HOL/ex/ROOT.ML	Tue Jul 28 18:17:36 2009 +0200
+++ b/src/HOL/ex/ROOT.ML	Tue Jul 28 19:49:42 2009 +0200
@@ -68,6 +68,7 @@
   "Landau"
 ];
 
+Future.shutdown ();
 (setmp_noncritical proofs 2 (setmp_noncritical Multithreading.max_threads 1 use_thy))
   "Hilbert_Classical";