pkey_ctrl_string
int pkey_ctrl_string(EVP_PKEY_CTX *ctx, char *value);
if (pkey_ctrl_string(pctx, keyopt) <= 0) {
if (pkey_ctrl_string(mac_ctx, macopt) <= 0) {
if (pkey_ctrl_string(pctx, sigopt) <= 0) {
if (pkey_ctrl_string(*cfg.ctx, arg) <= 0) {
} else if (pkey_ctrl_string(cfg.ctx, pkeyopt) <= 0) {
if (pkey_ctrl_string(pkctx, sigopt) <= 0) {
if (pkey_ctrl_string(genctx, genopt) <= 0) {