Logged In: YES 
user_id=21627

On POSIX platforms in general, detecting Unicode file name
support is not possible. Posix uses open(2), and only
open(2) (alon with creat(2), stat(2) etc) to access files.
There is no open_w, or open_utf8, or the like. So file names
are byte strings on Posix, and it will stay that way forever.
(There is actually also fopen, but that doesn't change the
situation at all).

On OSX, the situation is somewhat different from POSIX, as
you have additional functions to open files (which Python
apparently does not use, though), and because OSX specifies
that the byte strings have to be NFD UTF-8 (which Python
violates AFAICT).

The documentation for supports_unicode_filenames says

True if arbitrary Unicode strings can be used as file names
(within limitations imposed by the file system), and if
\function{os.listdir()} returns Unicode strings for a Unicode
argument.

While the first part is true for OSX, I don't think the
second part is. If that ever gets corrected (or verified),
no further detection is necessary - just set
macpath.supports_unicode_filenames for darwin (assuming you
use macpath.py on that system).