Hum, pep540-3.patch doesn't work if the locale encoding is different than ASCII and UTF-8. argv must be reencoded:
$ LC_ALL=fr_FR ./python -X utf8 -c 'import sys; print(ascii(sys.argv))' $(echo -ne "\xff")
['-c', '\xff']
The result should not depend on the locale, it should be the same than:
$ LC_ALL=fr_FR.utf8 ./python -X utf8 -c 'import sys; print(ascii(sys.argv))' $(echo -ne "\xff")
['-c', '\udcff']
$ LC_ALL=C ./python -X utf8 -c 'import sys; print(ascii(sys.argv))' $(echo -ne "\xff")
['-c', '\udcff']