Using varying structs can cause shader errors

[eqrion]

I get shader errors on my windows machine when using structs as in/out between VS and FS shaders.

We replaced one of the instances of this in #1136 , which fixed my startup crash. But I still get errors for other shaders, usually ps_border with flat varying RectWithSize vBorderRect.

This is happening to me with WebRender on ANGLE, I believe it happens to others on OpenGL.

It would suck to go back to using untyped vec4's for all these cases, so it'd be nice to find a workaround. There might not be one and we might have to revert parts of c31376b.

[eqrion]

@kvark @glennw thoughts?

[sotaroikeda]

I also faced the problem on my win laptop.

[kvark]

I don't see a prospect of workaround, let's revert the varying structs to regular vectors, for now at least.
@nical - to document this in the driver bug registry ;)

[CAfromCA]

If you ever need to test against an Intel HD Graphics 3000 (Sandy Bridge iGPU), I have one and am willing to help.