> Temporary fixing issues with some third party libraries which use C code for files I/O (With filename as "mbcs" encoded bytes internally).
>
> Theses libraries generally call "filename.encode(sys.getfilesystemencoding())" or "os.fsencode(filename)" before sending filenames from Python to C code.

Hum, Python lacks a function to encode to/decode from the ANSI code page, something like codecs.code_page_encode() / code_page_decode() with CP_ACP. It would allow to get the same encoding in UTF-8 and legacy modes.