Stick a prototype for handleclock() in machine/clock.h and include it

interrupt.c to quiet a warning.

sys/ia64/ia64/interrupt.c

@@ -48,6 +48,7 @@
 #include <sys/ktr.h>
 #include <sys/mutex.h>
 
+#include <machine/clock.h>
 #include <machine/reg.h>
 #include <machine/frame.h>
 #include <machine/intr.h>

sys/ia64/include/clock.h

@@ -18,6 +18,7 @@ extern	int	adjkerntz;
 int	sysbeep __P((int pitch, int period));
 int	acquire_timer2 __P((int mode));
 int	release_timer2 __P((void));
+void	handleclock __P((void *arg));
 
 #endif