RFC: Update Intel386, x86-64 and IA MCU psABIs for passing/returning empty struct

[Matthijs van Duin via cfe-commits]

On 19 February 2016 at 14:35, Michael Matz <matz at suse.de> wrote:
> struct S {
>   S() {something();}
> };
>
> would be an empty type, and that's not what we want.

Why not? The default constructor is never invoked as part of passing
such an object around. Its copy constructor is a nop and requires no
reference to the original object.

Matthijs van Duin