[Bug target/109558] bpf: support BTF and DWARF tag annotations for BPF

[david.faust at oracle dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109558

--- Comment #1 from David Faust <david.faust at oracle dot com> ---
v1 patch series for btf_decl_tag:

https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624156.html

This also adds infrastructure which will be used for btf_type_tag.