LibreSSL 2.7 implements OpenSSL 1.1 API except for BIO_get_init()
See also: https://bugs.freebsd.org/226900
Signed-off-by: Bernard Spil <brnrd@FreeBSD.org>
Closes: #617 (cherry-pick)
(cherry picked from commit 28b8075400c70b2d2da2ce07e590c2ec6d11783d)
Before it depends from the caller #include appropriate headers (at least
for OPENSSL_VERSION_NUMBER), but let's make it independent.
Fixes: #574
(cherry picked from commit c2c08e0203da93938fe35234fa3a1be4d1c3c2e1)