diff -r 4c8295f2f849 -r e48d93811ed7 src/Pure/Tools/generated_files.ML
--- a/src/Pure/Tools/generated_files.ML	Sat Oct 03 23:01:40 2020 +0100
+++ b/src/Pure/Tools/generated_files.ML	Mon Oct 05 21:15:58 2020 +0200
@@ -147,7 +147,7 @@
 fun write_file dir (file: file) =
   let
     val path = Path.expand (Path.append dir (#path file));
-    val _ = Isabelle_System.mkdirs (Path.dir path);
+    val _ = Isabelle_System.make_directory (Path.dir path);
     val _ = File.generate path (#content file);
   in () end;