loader/dri3: do not blit outside old/new buffers
This was discovered while hacking on Zink, where out-of-range blits cause validation errors.
It seems better to solve this problem at the root cause than fixing it in each driver.
This was discovered while hacking on Zink, where out-of-range blits cause validation errors.
It seems better to solve this problem at the root cause than fixing it in each driver.