diff -r 29bb1ebb188f -r efd995488228 src/CTT/ROOT
--- a/src/CTT/ROOT	Sun Sep 08 13:07:03 2019 +0200
+++ b/src/CTT/ROOT	Sun Sep 08 16:49:05 2019 +0200
@@ -16,6 +16,7 @@
     Simon Thompson, Type Theory and Functional Programming (Addison-Wesley,
     1991)
   "
+  directories "ex"
   options [thy_output_source]
   theories
     CTT