[glsl-in] Support anonymous global uniforms

[pjoe]

Partly handles issue in #210

Example shader:

#version 450

layout(set = 0, binding = 0) uniform Matrices {
    mat4 modelViewProjection;
};

layout(location = 0) in vec2 position;

void main() {
    gl_Position = modelViewProjection * vec4(position, 0.0, 1.0);
}

[kvark]

Could you post an example code of what you are trying to support in this PR?

[kvark]

Would it be possible, instead of calling lookup_global_struct_member here, make sure these fields are present in the lookup_global_var_exps table. I.e. once we encounter an anonymous global struct, just make sure we add the members to that map, and avoid any wacky lookups later on.

[pjoe]

Will take a look 👀
First step was to make it work :)

[pjoe]

Done. Simpler code - though a bit sad to see all my fancy FP code gone 😁

[pjoe]

Done. Simpler code - a bit sad to see all my fancy FP fun gone though 😁