diff --git a/tools/Makefile b/tools/Makefile
index c31437e..686840a 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -21,7 +21,7 @@
 # MA 02111-1307 USA
 #
 
-TOOLSUBDIRS =
+TOOLSUBDIRS = kernel-doc
 
 #
 # Include this after HOSTOS HOSTARCH check