[Issue 19179] extern(C++) small-struct by-val uses wrong ABI

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=19179

--- Comment #3 from Manu <turkeyman at gmail.com> ---
I think what should probably happen here, is that while the type in D is POD,
the counterpart in C++ is not POD because default initialisation generates a
constructor.

Perhaps the proper solution is to make the D struct emit a default constructor
(this just assign's init), and also force the type to use the non-POD ABI?
This way semantics will match C++, and if the C++ class externs to the default
constructor; it will link as they expect.

--