x11drv: Add stretching support to AlphaBlend

[Huw D M Davies]

On Sun, Oct 17, 2004 at 10:34:28PM -0400, Kevin Koltzau wrote:
> Changelog:
>  Add stretching support to AlphaBlend

XRenderSetPictureTransform is a relatively new addition to libxrender,
arriving just before XFree 4.3.  I don't think we want the whole
xrender stuff to fail if this specific function isn't available in the
library.  Could you make the presence of this function optional and
simply skip the stretched AlphaBlend if it's not there?

Huw.