[PATCH v2][PR gdb/23210] Unset gdbarch significant_addr_bit by default

[Pedro Alves]

On 05/26/2018 01:58 AM, Omair Javaid wrote:
> This version fixes the typo and gdbarch.sh issue highlighted in review.
> 
> LGTM?

I think the resulting API ends up a little weird.  Maybe a better
fit would be something around:

 CORE_ADDR gdbarch_canonical_address (gdbarch *, CORE_ADDR addr);

with the default implementation being a nop [return ADDR] while
Aarch64's implementation would clear the tag and sign extend.

Dunno, not sure, I really did not think that through, and, as
I mentioned before, I'm totally OK with this as is, we understand
the issues and can always change it later.

More important right now is unbreaking 32-bit x86 and the branch.

Thus, OK as is.  Please push to master and branch.

Thanks,
Pedro Alves