Mention graphviz somewhere as a dependency for gegl:introspect to work
From looking at 1f50456d , one can see that now
gegl:introspect won't be reported as available when the
dot executable can't be found in
PATH. This means that, for unaware users, GIMP can suddenly stop working when they update to 0.4.28, because it checks for
gegl:introspection at launch time. While I agree that having it as a build time dependency is bad (after all, I can be building a distribution package or cross compiling to a different device, so whatever is available locally doesn't matter), there aren't any docs (or explicit release notes: https://gitlab.gnome.org/GNOME/gegl/-/blob/master/docs/NEWS.txt mentions
dot becoming a runtime dep, but not exactly what difference it makes) that make it clear what
dot is necessary for (and it is an important dep; most users of gegl will want to have
dot, since GIMP is probably its main user).
Furthermore, the test suite seems to behave the same way when run with
dot available or not, so it doesn't help much in catching this issue.
I believe it would be of great helper to users and packagers for graphviz/dot to be listed as explicit dependencies. Probably in https://gitlab.gnome.org/GNOME/gegl/-/blob/master/docs/build.txt , at least? The project's docs seem to be a bit outdated in general, unfortunately.
I can make a PR to add this, if you think it fits.