diff -r f151ade98b15 -r e760242101fc src/Pure/Tools/check_source.scala
--- a/src/Pure/Tools/check_source.scala	Fri May 02 19:30:34 2014 +0200
+++ b/src/Pure/Tools/check_source.scala	Fri May 02 19:51:40 2014 +0200
@@ -40,7 +40,7 @@
 
   def check_hg(root: Path)
   {
-    System.err.println("Checking " + root + " ...")
+    Output.writeln("Checking " + root + " ...")
     Isabelle_System.hg("--repository " + Isabelle_System.shell_path(root) + " root").check_error
     for {
       file <- Isabelle_System.hg("manifest", root).check_error.out_lines