[patch] Rename and improve emitSectionOffset

[Duncan P. N. Exon Smith]

> On 2015-Jun-16, at 12:54, Rafael Espíndola <rafael.espindola at gmail.com> wrote:
> 
> Different object formats represents references from dwarf in different ways.
> 
> ELF uses a relocation to the referenced point (except for .dwo) and
> COFF/MachO use the offset of the referenced point inside its section.
> 
> The attached patch renames emitSectionOffset because
> 
> * It doesn't produce an offset on ELF.
> * It changes behavior depending on how DWARF is represented, so adding
> dwarf to its name is probably a good thing.
> 
> The patch also adds an option to force the use of offsets.That avoids
> funny looking code like
> 
>  if (!UseOffsets)
>    Asm->emitSectionOffset....
> 
> It was correct, but read as if the ! was inverted.
> 
> Cheers,
> Rafael
> <t.patch>

Great cleanup; thanks.  LGTM!