BIO_dup_chain
BIO * BIO_dup_chain(BIO *in);
LCRYPTO_ALIAS(BIO_dup_chain);
if ((dbio = BIO_dup_chain(c->bio_chain)) == NULL)
LCRYPTO_USED(BIO_dup_chain);
if ((dup = BIO_dup_chain(bio[0])) == NULL) {
if ((dup = BIO_dup_chain(bio[0])) != NULL) {