diff --git a/doc/manual/Makefile b/doc/manual/Makefile
new file mode 100644
index 0000000000..8e5e1f0bce
--- /dev/null
+++ b/doc/manual/Makefile
@@ -0,0 +1,3 @@
+DOCBOOK_DTD = /nix/current/xml/dtd/docbook
+DOCBOOK_XSL  =/nix/current/xml/xsl/docbook/
+