[PATCH] D19490: ELF: Teach section GC to also GC shared symbols.

[Rafael Espíndola via llvm-commits]

> That all makes sense when we see a definition both in the object files and
> the DSO, but I don't see why it should apply in the case where we only see a
> definition in the DSO.

Why only for definitions? This is not a very common case and I think
it would make the code a lot simpler.

Cheers,
Rafael