This commit makes sure we can properly run the tests in a headless
environment, i.e. they don't mess with the user's X display or their
session bus. The latter is also needed for parallel tests as they fail
to simultaneously own the same name on the session bus.
Replaced the "xvfb-run" meson option with the "headless" option, which
is more intuitive (and also more correct, since we now also require
`dbus-run-session` to run the tests, not only `xvfb-run`).
Finally, note that we need a version of `xvfb-run` that supports the
`-d` (`--auto-display`) option. The problem with `--auto-servernum`
which is also regularly used, is that it doesn't shut down cleanly,
returning a non-zero exit code, wich makes the test fail.
Fixes https://gitlab.gnome.org/GNOME/gimp/-/issues/5078
When we build GIMP with `-Dauto_features=enabled` to ensure we have
fully-featured GIMP and to have it warn us when we are missing some
optional dependency, Meson also enables relocatable bundle.
This is unexpected since being relocatable is a binary property rather
than a feature. This patch switches it option to a combo type to make
it ignore auto_features option.
It must not be a boolean but a `feature` option, with `auto` by default.
`auto` value mean enabled for macOS and Win32, and disabled for other
cases. This default logics disappeared in the meson build.
Also the mypaint-brushes package is a mandatory dependency, which must
always be checked. Absence is fatale.
Finally properly set the MYPAINT_BRUSHES_DIR macro depending on the
proper relocatable case.
Niels De Graef