vrend: match Mesa gbm header
requested to merge gurchetansingh/virglrenderer:gurchetansingh/virglrenderer-virgl-gbm-header into master
We can now use gbm_bo_map(..) directly to match Mesa.
If minigbm doesn't define the needed use flags, we define it internally.
This should allow us to build with minigbm allocation enabled and use the Mesa gbm header.
Reviewed-by: Gert Wollny gert.wollny@collabora.com