This allows libseat users to e.g. advise people to chmod a+s the
executable if libseat is built with the builtin backend.
While bumping the Meson version, adjust the scdoc logic to avoid
the following warnings:
WARNING: Project targeting '>=0.56.0' but tried to use feature deprecated since '0.56.0': Dependency.get_pkgconfig_variable. use Dependency.get_variable(pkgconfig : ...) instead
WARNING: Project targeting '>=0.56.0' but tried to use feature deprecated since '0.55.0': ExternalProgram.path. use ExternalProgram.full_path() instead
Setting auto_features=disabled is supposed to disable all optional
dependencies. Since we aren't using a feature option here, we need
to manually add logic to disable logind in this case.
If -Dlogind=auto but systemd/elogind isn't available,
logind_provider would get set to the last item of the foreach loop.
This would incorrectly report "systemd: YES".
Allow package maintainers to explicitly select a logind provider
by passing -Dlogind=systemd or -Dlogind=elogind. In case both are
available (e.g. for distributions which support both), this makes
it possible to gte deterministic behavior.
By default, auto-detect the logind provider. That way, users which
have systemd or elogind installed get the backend built by default.
This is useful for headless testing, for instance with VKMS:
modprobe vkms
export WLR_DRM_DEVICES=/dev/dri/card1
export WLR_BACKENDS=drm
export LIBSEAT_BACKEND=noop
sway
We don't need any of the VT handling in this case.
elogind provides a libsystemd wrapper which is packaged by some distros.
For whatever reason using this wrapper instead of libelogind directly
causes compiler warnings to pop up. Checking for libelogind first
ensures that this wrapper is not used.
