Attached patch deprecates the Windows ANSI API (bytes API) in the nt module. Use Unicode filenames instead of bytes filenames to not depend on the ANSI code page anymore and to support any Unicode filename.

The patch changes also os.link(), os.rename() and os.symlink() to not accept two filenames of different types: require two Unicode filenames or two bytes filenames. It is an expected change, it did it to simplify the source code. I change it if necessary.