diff --git a/lib/libunbound/Makefile b/lib/libunbound/Makefile
index 4ce8fcb4ab92..0b7f92e3318f 100644
--- a/lib/libunbound/Makefile
+++ b/lib/libunbound/Makefile
@@ -1,48 +1,49 @@
 # $FreeBSD$
 
 PACKAGE=lib${LIB}
 # Vendor sources and generated files
 LDNSDIR= ${SRCTOP}/contrib/ldns
 UNBOUNDDIR= ${SRCTOP}/contrib/unbound
 
 # Hold my beer and watch this
 .PATH: ${UNBOUNDDIR} ${UNBOUNDDIR}/cachedb ${UNBOUNDDIR}/dns64 ${UNBOUNDDIR}/iterator ${UNBOUNDDIR}/sldns ${UNBOUNDDIR}/libunbound ${UNBOUNDDIR}/services ${UNBOUNDDIR}/services/cache ${UNBOUNDDIR}/util ${UNBOUNDDIR}/util/data ${UNBOUNDDIR}/respip ${UNBOUNDDIR}/util/storage ${UNBOUNDDIR}/validator 
 
 LIB=	unbound
 PRIVATELIB=
 PACKAGE=	unbound
 
 CFLAGS+= -I${UNBOUNDDIR} -I${LDNSDIR} -I${.OBJDIR}
 CFLAGS+= -I${SRCTOP}/usr.sbin/unbound
+CFLAGS+= -DOPENSSL_API_COMPAT=0x10100000L
 
 SRCS=	alloc.c as112.c authzone.c autotrust.c cachedb.c config_file.c \
 	configlexer.l configparser.y context.c dname.c dns.c dns64.c \
 	dnstree.c edns.c fptr_wlist.c infra.c iter_delegpt.c iter_donotq.c \
 	iter_fwd.c iter_hints.c iter_priv.c iter_resptype.c iter_scrub.c \
 	iter_utils.c iterator.c keyraw.c libunbound.c libworker.c \
 	listen_dnsport.c localzone.c locks.c log.c lookup3.c lruhash.c \
 	mesh.c mini_event.c modstack.c module.c msgencode.c msgparse.c \
 	msgreply.c net_help.c netevent.c outbound_list.c outside_network.c \
 	packed_rrset.c parse.c parseutil.c proxy_protocol.c \
 	random.c rbtree.c redis.c \
 	regional.c respip.c rpz.c rrdef.c rrset.c rtt.c sbuffer.c slabhash.c \
 	str2wire.c tcp_conn_limit.c timehist.c tube.c ub_event_pluggable.c \
 	val_anchor.c val_kcache.c val_kentry.c val_neg.c val_nsec.c \
 	val_nsec3.c val_secalgo.c val_sigcrypt.c val_utils.c validator.c \
 	view.c winsock_event.c wire2str.c
 
 WARNS?=	2
 NO_WTHREAD_SAFETY= true
 
 LIBADD=	ssl crypto pthread
 
 # Misnamed file in upstream source
 configlexer.l: configlexer.lex
 	${CP} ${.ALLSRC} ${.TARGET}
 CLEANFILES+= configlexer.l
 
 # Symbol prefix for lex and yacc
 LFLAGS= -Pub_c_
 YFLAGS= -pub_c_ -d
 
 .include <bsd.lib.mk>