This patch corrects the error in PyUnicode_EncodeCharmap which would result in a to-latin1 mapping even if the target character include these characters.
The patch looks OK (except for some minor cosmetic changes I would apply). My only problem with it is your copyright notice. AFAIK, patches to the Python core cannot contain copyright notices without proper license information. OTOH, I don't think that these minor changes really warrant adding a complete license paragraph. Wouldn't a line like "Additional changes to support decoding maps by Martin v. Loewis" suffice ? Which changes these are would be immediately clear by looking at the CVS history.