[PATCH xserver] On x86 targets, turn off SSE instructions for SlowBcopy

[Matt Turner]

On Sun, Jul 30, 2017 at 11:49 AM, Dimitry Andric <dimitry at andric.com> wrote:
> Some compilers (e.g. clang) will recognize the memcpy idiom in
> xf86SlowBcopy(), and optimize it into a loop using SSE instructions.
> This can cause "Illegal instruction" crashes under virtualization
> environments such as qemu/kvm.
>
> To prevent this, explicitly turn off SSE for SlowBcopy.c, when compiling
> for an x86 target.
>
> See also: https://bugs.freebsd.org/202643

Thanks. This is also reported in Gentoo's bug tracker as well:

Bugzilla: https://bugs.gentoo.org/570684