diff -ru ntp.orig/Makefile ntp/Makefile
--- ntp.orig/Makefile	2013-02-07 00:51:49.000000000 -0500
+++ ntp/Makefile	2013-02-07 00:52:43.000000000 -0500
@@ -56,6 +56,10 @@
 CONFIGURE_ARGS+=        --enable-ipv6
 .endif
 
+.if defined(WITH_SIGNING)
+CONFIGURE_ARGS+=	--enable-ntp-signd
+.endif
+
 .for D in ${NTP_DRIVERS}
 .if defined(WITH_${D})
 CONFIGURE_ARGS+=	--enable-${D}
diff -ru ntp.orig/Makefile.inc ntp/Makefile.inc
--- ntp.orig/Makefile.inc	2013-02-07 00:51:49.000000000 -0500
+++ ntp/Makefile.inc	2013-02-07 00:52:34.000000000 -0500
@@ -2,6 +2,7 @@
 
 OPTIONS=	NTPSNMPD	"Build and install ntpsnmpd" OFF \
 		SSL		"Enable SSL" ON \
+		SIGNING		"Enable time signing" OFF \
 		IPV6		"Enable IPv6" OFF \
   		BANCOMM		"Enable Datum/Bancomm bc635/VME interface" OFF \
   		GPSVME		"Enable TrueTime GPS receiver/VME interface" OFF \