[PATCH] [lld][core] sectionGroup support.

[Rafael Espíndola]

> This is comdat, where the name does matter. The groups here aren't
> influencing symbol resolution directly. The linker first removes
> bar.o's g1. Then symbol resolution proceeds as normal. If they were
> not comdat, this would be a multiple definition error (of g1, f1, f2,
> and d1).

So, can't we just error on non-comdat groups (error: no idea what to
do with this)? What are they used for?

Cheers,
Rafael