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
That one might actually be better, nice to know & thanks for the pointer! (I hope it actually goes somewhere…)
That one might actually be better, nice to know & thanks for the pointer! (I hope it actually goes somewhere…)