Control: tags -1 + patch

Hi. A glib maintainer responded to the bug report, and it turns out
emacs was using glib slightly incorrectly. I'm attaching a patch to fix
the issue, as suggested by the maintainer.

With this patch, the pselect() call in emacs does see the glib
notification as it should. There is still an issue (also in glib) where
this notification comes about 1 second after the actual file system
activity, so I'm keeping this bug open. The glib bug tracker entry about
THIS problem is here:

 https://bugzilla.gnome.org/show_bug.cgi?id=739322