Build is broken.

[Eric S. Raymond]

ntpd/refclock_irig.c.10.o: In function `irig_start':
refclock_irig.c:(.text+0x1f): undefined reference to `audio_init'
refclock_irig.c:(.text+0x41): undefined reference to `audio_show'
ntpd/refclock_irig.c.10.o: In function `irig_gain':
refclock_irig.c:(.text+0x213e): undefined reference to `audio_gain'
collect2: error: ld returned 1 exit status
-- 
		<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>