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Note, you can produce the same error on OS X or linux by setting 
PYTHONIOENCODING="", which effectively overrides the value returned 
nl_langinfo(CODESET). In pythonrun.c, create_stdio passes 
PYTHONENCODING, if set, on as the "encoding" value to TextIOWrapper. If 
no encoding was specified, TextIOWrapper uses the value returned by 
locale.getpreferrencoding(). It then calls PyCodec_IncrementalDecoder 
and the unknown (or empty) encoding is finally detected.
That raises the question of how far python should go in protecting the 
user. One *could* add a check in pythonrun.c to substitute some 
suitable default (UTF-8) if nl_langinfo(CODESET) returns an empty value. 
Or perhaps just abort there with a more meaningful error message.