dri2: Add token for DRI2BufferHiz

CC: Ian Romanick <idr@freedesktop.org>
CC: Kristian Høgsberg <krh@bitplanet.net>
Acked-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Chad Versace <chad@chad-versace.us>

include/GL/internal/dri_interface.h

@@ -692,6 +692,7 @@ struct __DRIswrastExtensionRec {
 #define __DRI_BUFFER_FAKE_FRONT_LEFT	7
 #define __DRI_BUFFER_FAKE_FRONT_RIGHT	8
 #define __DRI_BUFFER_DEPTH_STENCIL	9  /**< Only available with DRI2 1.1 */
+#define __DRI_BUFFER_HIZ		10
 
 struct __DRIbufferRec {
     unsigned int attachment;