community/mpd: allow configuration of real-time scheduling
Without this change MPD emits the following warnings using syslog:
daemon.err libsmbclient[3356]: exception: RTIOThread could not
get realtime scheduling, continuing anyway: sched_setscheduler
failed: Operation not permitted
daemon.err libsmbclient[3356]: exception: OutputThread could not
get realtime scheduling, continuing anyway: sched_setscheduler
failed: Operation not permitted
See also: https://www.musicpd.org/doc/html/user.html#real-time-scheduling
@clandmeter you are maintain community/mpd
are you OK with this change?