bug#35418: [PATCH] Don't poll auto-revert files that use notification

[Eli Zaretskii]

> From: Mattias Engdegård <mattiase@acm.org>
> Date: Mon, 29 Apr 2019 20:58:15 +0200
> Cc: Eli Zaretskii <eliz@gnu.org>, 35418@debbugs.gnu.org
> 
> A file has three hard links, /dir1/a, /dir1/b and /dir2/c. Then:
> 
> - A watch set on /dir1/a will report changes made to the file via any of the 
> three links (kqueue, inotify).
> - A watch set on /dir1 will report changes made to the file via /dir1/a and 
> /dir1/b, but not /dir2/c (inotify).

Just FTR, w32notify reports changes made through any of the 3 links
when it watches dir1.  This is consistent with MS documentation, which
says that changing the file's data are reflected to all the hard links
immediately.