--compress-debug-sections may generate bigger sections

[Cary Coutant]

> I noticed that --compress-debug-sections might generate bigger sections,
> depending on input. Shouldn't we use uncompressed data instead if
> the compressed one is bigger?

I thought about that, and it would be a reasonable thing to do once
we've rolled over to using a section type or flag. As it is, I was
reluctant to set things up where we might have, say, a .zdebug_info
and a .debug_abbrev section, as it might confuse some tools that
aren't yet aware of the compressed sections.

-cary