> I do know, but when you are working inside a zone, I am not sure you
> can count of that file being always present. Syslog even could be
> disabled or not available inside a zone.

Then you can just skip the test.

> I am thinking about how to manage OS's with no support for doors.
> Instead of conditionally compile the new STAT,

Lib/stat.py is a pure Python module. There is no compilation to do.
You just have to add the pure Python version of the C macro.
For the record, 0xd000 is (stat.S_IFSOCK + stat.S_IFIFO).

> I would rather have the function always available, but returning FALSE
> when the OS doesn't support doors.

Right.

> But what happen if you mount a Solaris filesystem in a nonsolaris
> machine?. Let say, a Solaris ZFS filesystem with doors, under
> linux/*bsd + ZFS?.

I guess S_ISDOOR would return True.