Found my first build parallelism bug in a `meson` / `ninja` project: https://github.com/nix-community/nixd/pull/662

There I learned that `ninja` has a great
$ ninja -t missingdeps
command. It reports all the missing dependencies after the build.

`ninja` infers those from the tools that can autogenerate dependencies at build time. The example is inferred used C include files from build C source files.

#nixd #bug