Re: [PATCH 0/4] MR310: hlsl: Define some intrinsics in HLSL.

[Francisco Casas (＠fcasas)]

Francisco Casas (@fcasas) commented about libs/vkd3d-shader/hlsl.c:
>          ERR("Failed to insert function overload.\n");
>      vkd3d_free(name);
>      return;
>  }

Note that we are triggering this ERR if we have multiple calls to the same intrinsic, e.g.:

```hlsl
float4 main(uniform float4 u) : sv_target
{
    return lit(u.x, u.y, u.z) + lit(u.x, u.y, u.z);
}
```
because we are declaring the internal multiple times.

Perhaps hlsl_compile_internal_function() should check if the internal with the given name is already compiled.