diff --git a/Documentation/Makefile b/Documentation/Makefile
index ddd365720..34f611fb3 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -1,3 +1,4 @@
+__nmk_dir ?= ../scripts/nmk/scripts/
 include $(__nmk_dir)/include.mk
 include $(__nmk_dir)/macro.mk