We advertised ARB_draw_buffers, but either fell back to software when
using this output, or assertion failed. Fixes glsl-fs-fragdata-1, and
failures in some webgl conformance tests.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=39024
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=34906
case PROGRAM_OUTPUT:
switch (inst->DstReg.Index) {
case FRAG_RESULT_COLOR:
+ case FRAG_RESULT_DATA0:
return UREG(REG_TYPE_OC, 0);
case FRAG_RESULT_DEPTH:
p->depth_written = 1;