diff --git a/README b/README
index 0674d44362..6d9d2db7b0 100644
--- a/README
+++ b/README
@@ -243,6 +243,9 @@ Building
 	should also "make depend".  If you're using Emacs, you might find
 	"make tags" helpful.
 
+	If you need to re-run configure please run "make distclean" first.
+	This will ensure that all the option changes take.
+
 	Building with gcc is not supported, unless gcc is the vendor's usual
 	compiler (e.g. the various BSD systems, Linux).