diff --git a/usr.bin/factor/Makefile b/usr.bin/factor/Makefile
index dd7466302263..f180c0f135e7 100644
--- a/usr.bin/factor/Makefile
+++ b/usr.bin/factor/Makefile
@@ -1,19 +1,20 @@
 #	@(#)Makefile	8.1 (Berkeley) 5/31/93
 # $FreeBSD$
 
 .include <src.opts.mk>
 
 PROG=	factor
 SRCS=	factor.c pr_tbl.c
 CFLAGS+=-I${SRCTOP}/usr.bin/primes
 
 .if ${MK_OPENSSL} != "no"
 CFLAGS+=-DHAVE_OPENSSL
+CFLAGS+=-DOPENSSL_API_COMPAT=0x10100000L
 LIBADD+=crypto
 .endif
 
 MAN=	factor.6
 MLINKS+=factor.6 primes.6
 .PATH:	${SRCTOP}/usr.bin/primes
 
 .include <bsd.prog.mk>