[PATCH] aarch64: Fix segfault on unicode symbols

[Nick Clifton]

Hi Alex,

> OK for master?

> gas/ChangeLog:
> 2020-07-02  Alex Coplan  <alex.coplan@arm.com>
> 
> 	* config/tc-aarch64.c (reg_name_p): Fix cast so that we don't
> 	segfault on negative chars.
> 	* testsuite/gas/aarch64/reglike-label-unicode-segv.d: New test.
> 	* testsuite/gas/aarch64/reglike-label-unicode-segv.s: Input.

Approved - please apply.

Cheers
  Nick