diff --git a/Makefile b/Makefile
index 36cb3ff..cba6138 100644
--- a/Makefile
+++ b/Makefile
@@ -2,11 +2,11 @@
 #
 
 # You can set these variables from the command line, and also
-# from the environment for the first two.
+# from the environment for the first three.
 SPHINXOPTS    ?=
 SPHINXBUILD   ?= sphinx-build
+BUILDDIR      ?= build
 SOURCEDIR     = src
-BUILDDIR      = build
 
 # Put it first so that "make" without argument is like "make help".
 help: