[PATCH] D30419: [ELF] - Define __bss_start symbol.

[George Rimar via llvm-commits]

>Can you rebase this patch? It should be simpler now that BssSection is
>a SyntheticSection, since we should have a single .bss now.
>
>Cheers,
>Rafael

Rebased.

I changed logic a bit, so currently __bss_start points to .bss instead of bss.rel.ro,
if both sections exist, that helps to keep logic simple.

I suggest to try this before trying more complicated things. What do you think ?

George.