I dislike the double decoding, and would prefer if sys.argv would be
created directly from the wide command line.
In addition, I think the patch is incorrect: it ignores the arguments to
Py_Main, which is a documented API function.
One solution might be to declare all these functions (Py_Main,
SetProgramName, GetArgcArgv) to operate on Py_UNICODE*, and then
convert the POSIX callers of Py_Main to use mbstowcs when going
from the command line to Py_Main. WinMain could then become
recompiled for Unicode directly, likewise Modules/python.c