i2d_ASN1_SET_ANY
int i2d_ASN1_SET_ANY(const ASN1_SEQUENCE_ANY *a, unsigned char **out);
derlen = i2d_ASN1_SET_ANY(sk, &der);
LCRYPTO_ALIAS(i2d_ASN1_SET_ANY);
LCRYPTO_USED(i2d_ASN1_SET_ANY);