[Mesa-dev] i965 varying-index uniforms improvement

[Eric Anholt]

https://bugs.freedesktop.org/show_bug.cgi?id=61554

It's had more "me too"s than I would have expected, so I've marked all but
2 incidental patches as a candidate for 9.1.  It's also fairly invasive,
so I'm quite uncomfortable doing so.  I've tested on gm45, snb, and ivb so
far, and it seems to be working, though.  The previous iteration of the
IVB changes have been confirmed to fix the regression, and I hope to hear
back on pre-IVB soon.

The branch is at fs-varying-uniform-gen4 of my tree.