Use a cube instead of a quad in tessellation test.
A way to set partitioning/output_primitive info in eval shader.

dcl_tessellator_partitioning and dcl_tessellator_output_primitive appear
in hull shader for D3D,
but they appear on inputs inside domain shaders for GL.
Use HLSLCC_FLAGS to set the paritioning and primitive type. The correct
values to use
can be extracted from the hull shader reflection information.
Partial support for explicit input and output locations

i.e. layout(location = X) out/in.
Currently does not handle arrays correctly.
In/out layout locations were being applied to certain built-ins
Return 0 from HaveInOutLocationQualifier until the feature is ready.