Define a general entity "&version;" that can be used as the current major
version of the Python interpreter.  This is \version in the LaTeX format
of the documentation.
diff --git a/Doc/sgml/python.dtd b/Doc/sgml/python.dtd
index e9bf50a..88aace0 100644
--- a/Doc/sgml/python.dtd
+++ b/Doc/sgml/python.dtd
@@ -7,6 +7,11 @@
 	  PUBLIC "-//OASIS//DTD Exchange Table Model 19960430//EN">
 &oasis-tables.mod;
 
+<!-- define the &version; general entity -->
+<!ENTITY python-version.ent
+	  PUBLIC "+//IDN python.org//ENTITIES Python Version//EN">
+&python-version.ent;
+
 <!ELEMENT input - - EMPTY>
 <!ATTLIST input
 	  %common.att;