EVP_PKEY_CTX_ctrl_str
int EVP_PKEY_CTX_ctrl_str(EVP_PKEY_CTX *ctx, const char *type,
LCRYPTO_ALIAS(EVP_PKEY_CTX_ctrl_str);
LCRYPTO_USED(EVP_PKEY_CTX_ctrl_str);
rv = EVP_PKEY_CTX_ctrl_str(ctx, stmp, vtmp);