ldns: Belatedly update for OpenSSL 3.0.0

MFC after: 1 week
Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D57168

(cherry picked from commit cbe037c970580efc40eeca4715ac51e4d0fea082)

ldns: Mark these commits as merged

(cherry picked from commit 2bc6aa3c41d0dc330fefa6363a23d2cfa0253f73)
(cherry picked from commit 597a090ff2ab868242e4ec1cdec7469edbe41c50)
(cherry picked from commit 399f9ca49b6ecc7fc9bd8b2a0fd487fea4570a65)
(cherry picked from commit f103898935e1b709adbdaed5e0b10f99a17b9a4a)