List Texinfo 4.7 or later as optional.

diff --git a/README b/README
index 9ab9d07b06d5398299bbe5feec262938ffed81c8..a16158b869afbf0475450bb2bd70979d3b480973 100644 (file)
--- a/README
+++ b/README
@@ -35,6 +35,9 @@ PSPP, you will need to install certain prerequisites:
       have these installed, you must run `configure' with
       --without-gui.
 
+    * Optional: Texinfo 4.7 or later, if you want to build the
+      documentation in PostScript or PDF format.
+
 For information on differences from previous versions, please see file
 NEWS.  Full documentation on PSPP's language can be found in the doc/
 directory.