simultaneous use_thys;

--- a/src/ZF/ROOT.ML	Mon Feb 11 21:32:10 2008 +0100
+++ b/src/ZF/ROOT.ML	Mon Feb 11 21:32:11 2008 +0100
@@ -8,6 +8,5 @@
 Paulson.
 *)
 
-use_thy "Main";
-use_thy "Main_ZFC";
+use_thys ["Main", "Main_ZFC"];