Fix compilation with gcc 4.1. This is imported on the vendor branch as it

was applied in the mainstream source and a later complete import of
4.2.2p3 will complete the fix.

Submitted by:	kan

contrib/ntp/include/ntp_stdlib.h

@@ -134,8 +134,10 @@ extern u_char *	cache_key;		/* key pointer */
 extern u_int	cache_keylen;		/* key length */
 
 /* clocktypes.c */
+#ifdef NTP_REFCLOCK_H
 struct clktype;
 extern struct clktype clktypes[];
+#endif
 
 /* getopt.c */
 extern char *	ntp_optarg;		/* global argument pointer */

contrib/ntp/include/ntpd.h

@@ -226,8 +226,10 @@ extern int	config_priority;
 #endif
 
 /* ntp_control.c */
+#if 0
 struct ctl_trap;
 extern struct ctl_trap ctl_trap[];
+#endif
 extern int	num_ctl_traps;
 extern keyid_t	ctl_auth_keyid;		/* keyid used for authenticating write requests */