Jeff,

I've just committed the attached.  It fixes two bugs when using xfer 
partial in an existing target.

- the "add_target" method was always overriding the child's 
to_xfer_partial method.  The consequence is that the code your patch 
adds is never called!

- the code would all off the end of a stack which this part of the 
change fixed: * target.c (init_dummy_target): Initialize to_xfer_partial 
to default.

I've one more tweak to the target code.  Once thats in can you please 
confirm that this new child method is called and is needed - seems 
things work without it?

Andrew