In Mesa, this extension is implemented purely in software. Drivers may
*optionally* provide optimized paths.
NOTE: This has the side effect of enabling the extension in the radeon,
r200, and nouveau drivers.
v2: Minor whitespace tidying (suggested by Brian).
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Brian Paul <brianp@vmware.com>