diff --git a/usr.sbin/watchdogd/Makefile b/usr.sbin/watchdogd/Makefile
index be69d2bf5a8..5df7946cb1f 100644
--- a/usr.sbin/watchdogd/Makefile
+++ b/usr.sbin/watchdogd/Makefile
@@ -4,8 +4,8 @@ PROG=	watchdogd
 LINKS=	${BINDIR}/watchdogd ${BINDIR}/watchdog
 MAN=	watchdogd.8 watchdog.8
 
-LDADD=	-lm -lutil
-DPADD=	${LIBM} ${LIBUTIL}
+LDADD=	-lutil
+DPADD=	${LIBUTIL}
 
 .include <bsd.prog.mk>
 
diff --git a/usr.sbin/watchdogd/watchdogd.c b/usr.sbin/watchdogd/watchdogd.c
index cce84e1d9a1..8194f963a56 100644
--- a/usr.sbin/watchdogd/watchdogd.c
+++ b/usr.sbin/watchdogd/watchdogd.c
@@ -48,6 +48,7 @@ __FBSDID("$FreeBSD$");
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <strings.h>
 #include <sysexits.h>
 #include <unistd.h>
 
@@ -280,7 +281,7 @@ parseargs(int argc, char *argv[])
 			if (a == 0)
 				timeout = WD_TO_NEVER;
 			else
-				timeout = 1.0 + log(a * 1e9) / log(2.0);
+				timeout = flsll(a * 1e9);
 			if (debugging)
 				printf("Timeout is 2^%d nanoseconds\n",
 				    timeout);