Thanks but I'm not asking for a better way to handle #ifdef's, indenting them is extra work¹ and there's still an unnecessary outermost block for the include guard. You've also not made any further argument against the use of "#pragma once".
¹ especially across an open source project with more than a hundred contributors from a multitude of companies.
Then indent your macros for readability. clang-format can do it for you if you don't want to maintain them.