C++ interop - class vs struct

[Walter Bright via Digitalmars-d]

C++ name mangling distinguishes between a class and a struct. This distinction 
has no semantic meaning, but there it is in the name mangling. In order to 
interop, we have to have a way to tell D to mangle a struct as a 'class' when 
interfacing with C++.

I have some ideas, but they're all kinda ugly.

Any ideas?