`sm::CpuAligned` not implemented for `!Sized + sm::CpuLayout` structs

[RayMarch]

trafficstars

the trait sm::CpuAligned is not public and not implemented for !Sized + sm::CpuLayout structs.

as of now, the following code doesn't compile

#[derive(sm::CpuLayout)]
#[repr(C)]
struct Unsized {
    a: f32,
    b: [f32],
}
< Unsized as sm::CpuAligned>::CPU_ALIGNMENT;

Solution:

• add sm::CpuAligned to the public interface.
• add an impl block for sm::CpuAligned in the #[derive(sm::CpuLayout)] macro that takes the same bounds as the impl block for sm::CpuLayout and infers the alignment and optional size from the fields.