added Quickcheck_Benchmark (cf. 1959baa22632);

--- a/src/HOL/ROOT	Sat Jul 28 20:20:35 2012 +0200
+++ b/src/HOL/ROOT	Sat Jul 28 20:27:39 2012 +0200
@@ -734,7 +734,12 @@
 
 session Quickcheck_Examples = HOL +
   options [document = false]
-  theories Quickcheck_Examples  (* FIXME *)
+  theories
+    Quickcheck_Examples (* FIXME more *)
+
+session Quickcheck_Benchmark = HOL +
+  theories [condition = ISABELLE_BENCHMARK]
+    Find_Unused_Assms_Examples  (* FIXME more *)
 
 session Quotient_Examples = HOL +
   description {*