Mhm. Putting the dummy member into the embedded node doesn't give a path from the proper object to find the embedded node "mid-struct". run-time checks are the "easy way out". We/I'll stick to macro soup probably, so we have compile-time checks.
btw. For ISO C WG14… has anyone suggested adding _Include to the preprocessor, along the lines of _Pragma? It'd really help with doing this kind of really long macros, hiding the clunky "#define, #define, #define, #include" inside a macro…
I don't think anybody has proposed this, at least not recently. There is a proposal for multi-line macros: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3531.txt