I hand applied the patch because I hoped it would fix the problem of the 
cursor going all the way to the left of the >>> in the Python shell when 
you press home or ctrl-a.  The patch as it is does not solve this problem 
on the Mac.  I've uploaded the patch as a unified diff to make it easier 
for others who might want to give it a try.

The patch does a great job of scrolling through the history at the current 
prompt.  This is a great improvement!  Thanks.