PEM_read_bio_X509_CRL
if ((crl = PEM_read_bio_X509_CRL(bio, NULL, NULL, NULL)) == NULL)
x = PEM_read_bio_X509_CRL(in, NULL, NULL, NULL);
crl = PEM_read_bio_X509_CRL(in, NULL, NULL, NULL);
x = PEM_read_bio_X509_CRL(in, NULL, NULL, "");