Add comment to Distutil files about requiring 1.5.2 compatibility, as
    suggested by PEP 291.
diff --git a/Lib/distutils/spawn.py b/Lib/distutils/spawn.py
index f94817d..6e0423b 100644
--- a/Lib/distutils/spawn.py
+++ b/Lib/distutils/spawn.py
@@ -6,6 +6,8 @@
 executable name.
 """
 
+# This module should be kept compatible with Python 1.5.2.
+
 __revision__ = "$Id$"
 
 import sys, os, string