While waiting for the configured ALSA card to become available, use
inotify and watch for CREATE events on /dev/snd instead of
polling (using a timeout in the poll(3) call).
Note that we don’t know the actual names of the files that (will) be
created. This means:
* Every time we see a CREATE event on /dev/snd, we *try* to connect to
ALSA. If we fail, we go back to watching /dev/snd again.
* ALSA (not yambar) will log an error message each time we fail.