A work-around when using python from a shell environment (e.g. from a
bash shell in Terminal) is to issue

export __CF_USER_TEXT_ENCODING=0x1F5:0:0

before starting python. I haven't yet worked out how to apply this to
GUI apps. I tried editing ~/.MacOSX/environment.plist and
~/.CFUserTextEncoding but neither strategy prevents the crash.

I assume the fix works because it means one of the explicitly listed
encodings matches so things never get as far as the code which triggers
the error.

Without the fix, my environment contained

__CF_USER_TEXT_ENCODING=0x1F5:39:79

which does not, apparently, correspond to any of the encodings
explicitly listed in _localemodule.c.

- cfr