btf__add_typedef
LIBBPF_API int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id);
btf__add_typedef(btf2, "et", 9); /* [23] typedef enum (anon) */
btf__add_typedef(btf2, "arraytype", 15); /* [28] typedef int[3] foo; */
myint_id = btf__add_typedef(split_btf, "myint", int_id);
btf__add_typedef(btf, "t", 1); /* [9] typedef int t; */
id = btf__add_typedef(btf, "typedef1", 1);