This is useful at the maximum depth level, to update newly created
directories.  It is however questionable if the hard-coded 5 seconds
delay is enough to create new directory trees with all of their files,
but we might make that delay configurable in the future.

Limits the depth of the watched directories.  This is useful to keep
resource usage down and speed up MPD startup.

All sources which might work with large files must include config.h,
to get Large File Support on 32 bit platforms.

This patch implements a light-weight inotify library, and watches all
directories below the music directory.  It updates all directories
where files changed after a delay of 5 seconds.