ASN1_EX_COMBINE in OpenSSL 1.1.1c?

[weber at infotech.de]

Dear users,

during migration from version 1.0.2s to 1.1.1c we are missing the makro 
ASN1_EX_COMBINE.

It was used to embed a choice in a sequence as follows:
> ASN1_CHOICE(X509AT_ATTRIBUTE_SET) = {
>     ASN1_SET_OF(X509AT_ATTRIBUTE, value.set, ASN1_ANY),
>     ASN1_SIMPLE(X509AT_ATTRIBUTE, value.single, ASN1_ANY)
> } ASN1_CHOICE_END_selector(X509AT_ATTRIBUTE, X509AT_ATTRIBUTE_SET, single)
>
> ASN1_SEQUENCE(X509AT_ATTRIBUTE) = {
>     ASN1_SIMPLE(X509AT_ATTRIBUTE, object, ASN1_OBJECT),
>     /* CHOICE type merged with parent */
>     ASN1_EX_COMBINE(0, 0, X509AT_ATTRIBUTE_SET)
> } ASN1_SEQUENCE_END(X509AT_ATTRIBUTE)

What's the proper substitute in 1.1.1c?

Thanks in advance
-- Christian Weber