[PATCH][GAS] aarch64: Add +pauth flag for Pointer Authentication feature

[Nick Clifton]

Hi Przemyslaw,

> New -march option +pauth enables PAuth vel PAC (Pointer Authentication)
> feature.

> OK for master ?

I think that you also need to update gas/doc/c-aarch64.texi to include
a mention of this new extension option.  Approved with that change.

> gas/ChangeLog:
> 
> 2020-11-13  Przemyslaw Wirkus  <przemyslaw.wirkus@arm.com>
> 
> 	* NEWS: Update news.
> 	* config/tc-aarch64.c: Add option +pauth to -march.
> 	* testsuite/gas/aarch64/pac-feat.d: New test.
> 	* testsuite/gas/aarch64/pac-feat.s: New test.
> 

Cheers
   Nick