alt Hacker News> ninja can be used via cmake too but most uses I see are from meson
How do you know though when the choice of cmake-generator is entirely up to the user? E.g. you can't look at a cmake file and know what generator the user will select to build the project.
FWIW I usually prefer the Ninja generator over the Makefile generator since ninja better 'auto-parallelises' - e.g. with the Makefile generator the two 'simple' options are either to run the build single-threaded or completely grind the machine to a halt because the default setting for 'parallel build' seems to heavily overcommit hardware resources. Ninja just generally does the right thing (run parallel build, but not enough parallelism to make the computer unusable).
ninja supports separate build groups and different max number of parallel jobs for each. CMake's ninja generator puts compilation and linking steps in their own respective groups. End result is by default `nproc` parallel jobs for compilation but 1 job for linking. This helps because linking can be way more memory intensive or sometimes the linker itself has support for parallelism. Most projects have only a handful of linking steps to run anyway.