If you sort your fields by size or manually pad them with natural alignment, and use #pragma pack or equivalent non-standard directives that gets you most of the way there. But yes, avoid bitfields.
C++ "standard layout type" is the modern equivalent of "POD" I think.
GP probably meant "POD for the purpose of layout" in the Itanium ABI. It's not the same as standard layout, and POD is not a term in recent C++ standards.
C++ "standard layout type" is the modern equivalent of "POD" I think.