That's technically true, but you could just integrate the Ninja source code into such a meta build system and run it e.g. with a different command line option and then at the latest the attribute "meta" would be no longer relevant. "meta" in this context doesn't actually mean "on a meta level", but just that the tool is a transpiler from a high-level to a low-level build description, instead of a full execution engine. make (in contrast to Ninja) has features for both levels. Personally I would prefer an integrated system, so bootstrapping would not involve two (artificially) separate parts. But as I understand your message is that Beast is rather a Ninja alternative than a Cmake alternative. That's ok, although we already have Ninja and it claims to be a very fast build tool. So in the question we then just replace Cmake/Meson by Ninja.
> since I have already provided the cpp/h files generated by them on github!
Ok, I see. So it then also runs on Windows? How do you build the tool on Windows?
EDIT: actually if you're interested in GN, which has some very good concepts not seen elsewhere, I've written a tool to view and navigate GN source trees, see https://github.com/rochus-keller/GnTools. I usually use it with the Dart SDK source tree.