PyOS_snprintf() to avoid temporary buffer allocated on the stack and a
conversion from bytes to Unicode.

PyOS_snprintf().

doesn't have PY_SSIZE_T_CLEAN define and the size doesn't fit in an int
(length bigger than 2^31-1 bytes).

for expiration year greater than 2038 on 32-bit systems.

The argument was not used in the format string.

PyErr_SetFromWindowsErrWithFilenameObject() was never implemented.

Patch by Filip Gruszczyński.