diff --git a/dtool/LocalSetup.pp b/dtool/LocalSetup.pp
index b4cc60caa2..9a1192ccba 100644
--- a/dtool/LocalSetup.pp
+++ b/dtool/LocalSetup.pp
@@ -448,4 +448,7 @@ $[cdefine VC6_STYLE_ALLOCATOR]
 $[cdefine MODERN_STYLE_ALLOCATOR]
 $[cdefine NO_STYLE_ALLOCATOR]
 
+/* Define if you want to use Python before 2.3.  */
+$[cdefine USING_PYTHON_2_2_OR_EARLIER]
+
 #end dtool_config.h