diff --git a/sys/powerpc/include/clock.h b/sys/powerpc/include/clock.h
index a0918c901fa4..820a0d7d4ee0 100644
--- a/sys/powerpc/include/clock.h
+++ b/sys/powerpc/include/clock.h
@@ -1,26 +1,28 @@
 /*-
  * Kernel interface to machine-dependent clock driver.
  * Garrett Wollman, September 1994.
  * This file is in the public domain.
  *
  * $FreeBSD$
  */
 
 #ifndef _MACHINE_CLOCK_H_
 #define	_MACHINE_CLOCK_H_
 
 #ifdef _KERNEL
 
 extern	int	disable_rtc_set;
 extern	int	wall_cmos_clock;
 extern	int	adjkerntz;
 
+struct trapframe;
+
 int	sysbeep(int pitch, int period);
 int	acquire_timer2(int mode);
 int	release_timer2(void);
 
 void	decr_intr(struct trapframe *);
 
 #endif
 
 #endif /* !_MACHINE_CLOCK_H_ */