PATCH: Support SHF_GNU_COMPRESSED

[Cary Coutant]

>> My comment above is just as relevant to .zdebug.
>
> Current .zdebug* section uses PROGBITS. My patch simple follows
> the current scheme.

I think he's suggesting to add SHF_OS_NONCONFORMING to those sections.

That flag is supposed to indicate that the ELF consumer should refuse
to process the file if it doesn't understand the section type.
Applying SHF_OS_NONCONFORMING to an SHT_PROGBITS section would have no
effect, since all ELF consumers presumably know what SHT_PROGBITS
means. It would make sense if/when we change compressed debug sections
to use SHT_GNU_COMPRESSED_BITS.

-cary