XFRM support for IpSec polcy

Wish to reach out for support on adding policies in IpSec using XFRM ;
Observed that xfrm is packaged along with ip-full package and in our system we see that ip-full is enabled and also ip(Minimal) ;
We are not able to see xfrm support , hence adopted the approach listed in
with this we are able to add xfrm support ; however we see this approach is more manual in removing the packages ip-full and ip-tiny and then adding ip-full again ;
So the query is how we can make it as part of the Openwrt build system



Is it possible to add an XFRM interface using the manual approach?

The instruction seems quite long from the link.

Is there a short description?