improve previous note on windows build
diff --git a/docs/index.rst b/docs/index.rst
index 255c9e9..48ec0e4 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -18,7 +18,8 @@
 
     If you're on Windows you'll need to make sure you have OpenSSL installed.
     There are `pre-compiled binaries`_ available. If your installation is in
-    an unusual location ``set LIB=C:\OpenSSL-x.y.z\lib;%LIB%`` before installing.
+    an unusual location set the ``LIB`` and ``INCLUDE`` environment variables
+    to include the corresponding locations.
 
 
 Why a new crypto library for Python?