A new kind BTF_KIND_TAG is added to .BTF to encode
btf_tag attributes. The format looks like
CommonType.name : attribute string CommonType.type : attached to a struct/union/func/func_proto/var. CommonType.info : encoding BTF_KIND_TAG kflag == 1 to indicate the attribute is for CommonType.type, or kflag == 0 for struct/union member or func argument. one uint32_t : to encode which member/argument starting from 0.
If one particular type or member/argument has more than one attribute,
multiple BTF_KIND_TAG will be generated.