several changes today

[Thomas Bushnell, BSG]

   Date: Sun, 18 Oct 1998 20:04:58 -0400
   From: Roland McGrath <roland@frob.com>

   Of course I checked the standard before making authoritative claims about
   its contents, silly.  See 1003.1-1996 5.1.2.4, p 116.  The only "if
   detected" errors listed for `opendir' are EMFILE and ENFILE.  Listed
   as "if occur" errors are EACCES, ENAMETOOLONG, ENOENT, and ENOTDIR.

I just didn't have the standard at hand at it wasn't clear to me from
your messages whether you were making an authoritative claim or not...

So I agree, for the record, with your comments in this thread; on a
generic system (lacking O_DIRECTORY or other special features) an
fstat after the open is 100% obligatory.

On the Hurd we should not rely on that because the stat bits are only
suggestive; we should do an empty lookup instead.

Thomas