For parole and xfce4-screensaver, to be removed when these issues are
solved:
apps/parole#114
apps/xfce4-screensaver#153

Instead of adding them to each project, and thus having them as correct
.build extensions. This remains opt-in, with projects wishing to
activate these builds having to define (X11|WAYLAND)_FEATURE CI/CD
variables. I had originally thought of parsing configure.ac to detect
this, but it doesn't seem to be supported; maybe that's better.

Including on glib deprecation warnings, which are probably the only ones
we care about.

This assumes that XDT_FEATURE_DEBUG is used on all projects where
build_project.yml is included, which is currently the case.

This only applies to the build stage, as other distcheck-specific
warnings may appear that we don't necessarily want to turn into errors,
especially on vala projects. Also, this leaves open the possibility of
applying another debug level to distcheck, and thus compiling other code
paths.

By default, projects are configured so that a running pipeline is
interrupted if new changes are pushed in a merge request. But for this
to work in practice, all jobs in the pipeline must also be flagged
interruptible, otherwise the pipeline is not interrupted.

See https://docs.gitlab.com/ee/ci/yaml/index.html#workflowauto_cancelon_new_commit

Related: apps/orage#32

- More recent version of everything, should help to introduce new
  features.
- Bump docker dind (docker-in-docker) image used to build CI container
  itself

Probably a regression introduced in 2759f19c.

Fixes: #62

For xfce4-weather-plugin.

Related: panel-plugins/xfce4-weather-plugin!26

This is only useful for components packaged in flatpak in practice, i.e.
for Mousepad and Ristretto. There's no point in asking to update this
file if it's irrelevant.

Hopefully this will prevent releasing without changing the version
number.

For xfce4-indicator-plugin.

We use C99 features in various places (especially init-statement in for
loops), and C99 allows declaration after statement. This also avoids
warnings from other projects, like GObject Introspection >= 1.76.1 via
g-ir-scanner.

For gettext migration of project containing a policykit file.

Makes 'xfce-do-release' as well usable for xfwm4, which has some more
spaces in the line: 'm4_define([xfwm4_version_tag],   [git])'

MR !74