Attached patch makes dnotify compile-time configurable via
CONFIG_DNOTIFY.  The patch stands alone from the inotify patch, although
it really makes most sense in that context.  Maybe the tiny kernel will
find it useful as well.

On a desktop system with inotify, there is no reason to enable dnotify
support.  The primary user of dnotify (FAM) already supports inotify
(via Gamin).  Many non-desktop systems do not use dnotify.

There was a sysctl, dir_notify_enable, for run-time configuration of
dnotify.  I removed it.  It makes no sense to me, even without
compile-time configuration, to disable this feature.  With the ability
to compile dnotify away, a sysctl makes even less sense (which, as it
made zero sense before, makes no sense in and of itself now).

Disabling CONFIG_DNOTIFY saves a couple hundred bytes off of vmlinux.

When disabled, fcntl(fd, F_NOTIFY, ...) returns -EINVAL. 

Best,

	Robert Love