svga: implement TGSI_PROPERTY_FS_COLOR0_WRITES_ALL_CBUFS

Fixes several colorbuffer tests, including piglit "fbo-drawbuffers-none"
for "gl_FragColor" and "glDrawPixels" cases.

v2: rework patch to only avoid creating extra shader variants when
TGSI_PROPERTY_FS_COLOR0_WRITES_ALL_CBUFS is not specified.  Per Jose.
Use a write_color0_to_n_cbufs key field to replicate color0 to N
color buffers only when N > 0 and WRITES_ALL_CBUFS is set.

Reviewed-by: José Fonseca <[email protected]>

0 files changed, 0 insertions, 0 deletions