I've been using it to compile grabnim for  every combination of  linux
(gnu/musl), windows, macosx, haiku; arm64, x86_64, x86

and configuration is like two short nimscript files:

https://codeberg.org/janAkali/grabnim/src/branch/master/config.nims

https://codeberg.org/janAkali/grabnim/src/branch/master/zig_build_all.nims