Put libmd last in relayd's link order

libmd and libcrypto define some identical symbols, but they are not
source-compatible since libmd's functions do not have a return value,
while libcrypto's implementations always return 0.  OpenSSL checks these
return values, so when using libmd's implementations, it can fail in
mysterious ways.  Normally it's not a problem since libmd provides weak
symbols so if libmd.so and libcrypto.so are both linked, libcrypto's
implementations will be used.

FreeBSD's net/relayd port changes relayd's link line to statically link
LibreSSL.  It looks like this after patching:

LDADD= -lmd -L${PREFIX}/lib ${LIBEVENT} /usr/local/lib/libssl.a /usr/local/lib/libcrypto.a

When mixing libmd.so with the libcrypto.a archive like this, libmd's
symbols are used by LibreSSL, resulting in strange crashes.  Link
ordering rules are not really well defined when mixing dynamically and
statically linked libraries like this, as far as I know.  Moving libmd
to the end of the link order fixes the problem, so this diff fixes the
problem by doing just that.

src/usr.sbin/relayd/Makefile

@@ -50,7 +50,7 @@ CFLAGS+=	-I${.CURDIR} -I${.CURDIR}/../../lib/libutil \
 		-I${.CURDIR}/../../../libevent
 CLEANFILES+=	y.tab.h
 
-LDADD=		-lmd -L${PREFIX}/lib ${LIBEVENT} -lssl -lcrypto
+LDADD=		-L${PREFIX}/lib ${LIBEVENT} -lssl -lcrypto -lmd
 DPADD=		${LIBEVENT} ${LIBSSL} ${LIBCRYPTO}
 
 .include <bsd.prog.mk>