freedreno header uses not installed xf86atomic.h

[Eric Engestrom]

On Friday, 2019-02-15 07:11:55 -0500, Rob Clark wrote:
> On Fri, Feb 15, 2019 at 3:55 AM Daniel Drake <drake at endlessm.com> wrote:
> >
> > Hi,
> >
> > Using libdrm-2.4.97, mesa fails to build on ARM with:
> >
> > [  456s] In file included from
> > ../../../../../src/gallium/drivers/freedreno/freedreno_util.h:33,
> > [  456s]                  from
> > ../../../../../src/gallium/drivers/freedreno/freedreno_batch.h:34,
> > [  456s]                  from
> > ../../../../../src/gallium/drivers/freedreno/freedreno_context.h:39,
> > [  456s]                  from
> > ../../../../../src/gallium/drivers/freedreno/freedreno_program.c:33:
> > [  456s] /usr/include/freedreno/freedreno_ringbuffer.h:32:10: fatal
> > error: xf86atomic.h: No such file or directory
> >
> > The freedreno headers were recently modified to use xf86atomic.h:
> > https://gitlab.freedesktop.org/mesa/drm/commit/b541d21a0a908bf98d44375720f4430297720743
> >
> 
> oh, that union/ifdef hack was specifically to avoid this issue..
> probably the patch removing it should be reverted.

Right, I messed up with that commit, I didn't realise freedreno_ringbuffer.h
was installed. We need to remove that include.

That said, I'm confused as to how freedreno_ringbuffer.h users in Mesa
knows whether it's safe to use refcnt from that union?
It doesn't check for HAS_ATOMIC_OPS, so it can't know whether it
contains garbage padding or a refcount, can it?