X509_REQ_check_private_key
LCRYPTO_USED(X509_REQ_check_private_key);
int X509_REQ_check_private_key(X509_REQ *x509, EVP_PKEY *pkey);
LCRYPTO_ALIAS(X509_REQ_check_private_key);
if (selfsign && !X509_REQ_check_private_key(req, pkey)) {