Types only referenced by bindgen layout checks incorrectly handled

[bjorn3]

struct group {
    gr_name: *const u8,
    gr_passwd: *const u8,
    gr_gid: *const u8,
    gr_mem: *const u8,
}

#[allow(clippy::unnecessary_operation, clippy::identity_op)]
const _: () = {
    ["Size of group"][::std::mem::size_of::<group>() - 32usize];
    ["Alignment of group"][::std::mem::align_of::<group>() - 8usize];
    ["Offset of field: group::gr_name"][::std::mem::offset_of!(group, gr_name) - 0usize];
    ["Offset of field: group::gr_passwd"][::std::mem::offset_of!(group, gr_passwd) - 8usize];
    ["Offset of field: group::gr_gid"][::std::mem::offset_of!(group, gr_gid) - 16usize];
    ["Offset of field: group::gr_mem"][::std::mem::offset_of!(group, gr_mem) - 24usize];
};

results in

warning: struct `group` is never constructed
   --> src/pam/sys.rs:148:8
    |
148 | struct group {
    |        ^^^^^
    |
    = note: `#[warn(dead_code)]` on by default

which causes cargo-minify to remove the group struct which then results in a whole bunch of errors. Ideally the layout checks would be removed too, but if that is not possible, it should avoid removing group.