X509_VERIFY_PARAM_get0_host
const char *host = vpm == NULL ? NULL : X509_VERIFY_PARAM_get0_host(vpm, 0 /* first hostname */);
while ((str = X509_VERIFY_PARAM_get0_host(vpm, idx++)) != NULL)
char *X509_VERIFY_PARAM_get0_host(X509_VERIFY_PARAM *param, int idx);