Fixed bug in proof of support theorem (it failed on constructors with no arguments).

--- a/src/HOL/Nominal/nominal_package.ML	Mon Oct 17 17:42:24 2005 +0200
+++ b/src/HOL/Nominal/nominal_package.ML	Mon Oct 17 18:34:51 2005 +0200
@@ -1769,6 +1769,7 @@
             (fn _ =>
               [simp_tac (HOL_basic_ss addsimps (supp_def ::
                  Un_assoc :: de_Morgan_conj :: Collect_disj_eq :: finite_Un ::
+                 refl :: symmetric empty_def :: Finites.emptyI :: simp_thms @
                  abs_perm @ abs_fresh @ inject_thms' @ perm_thms')) 1])
         in
           (supp_thm,