[lld] r249093 - [elf2] Ignore --{start,end}-group.

[Rafael Espíndola via llvm-commits]

> There are options on the list that are intentionally nops and some now,
> that are not implemented, but should be. The latter at least should be
> something like MissingFlag or so.

No. They are there because there are more pressing issues and putting
them there makes it easier for us to work on the later ones.

They should be whatever is most convenient to us, the people actually
coding this.

Cheers,
Rafael