CONFIG_ARCH_SUPPORTS_INT128 for AArch64

[Jason A. Donenfeld]

Hi Mark,

On Tue, Oct 31, 2017 at 11:43 AM, Mark Rutland <mark.rutland at arm.com> wrote:
> Judging by Documentation/kbuild/makefiles.txt, we could do something
> like the below in the arm64 Makefile:
>
> cflags-y += $(call cc-ifversion, -ge, 0500, -DCONFIG_ARCH_SUPPORTS_INT128)

Okay, in that case, I'll re-research the gcc commit that made int128
work properly on aarch64, confirm the release version, and then submit
a patch doing this.

Jason