gnome-terminal fails to start under sway on core-updates-frozen

Hi Guix,

With core-updates-frozen commit b033079e47357dcf77ebeeb52b0a5306cd6aa982

gnome-terminal fails to start under sway either as launched from gdm or

directly from a vt with `dbus-run-session sway`.

```

$ gnome-terminal

# Error constructing proxy for org.gnome.Terminal:/org/gnome/Terminal/Factory0: Error calling StartServiceByName for org.gnome.Terminal: Process org.gnome.Terminal exited with status 10

```

It works correctly in a gnome session.

Best,

Jack

On Mon, 22 Nov 2021, Jack Hill wrote:

Josselin Poiret determined [0] that the root cause of this behavior is

that gnome-terminal is being launched via dbus, but the bus doesn't know

about the wayland display, so can't start graphical applications.

Everything works as expected if dbus is told about the display, which can

be done by adding the following like to the sway configuration:

```

exec dbus-update-activation-environment WAYLAND_DISPLAY

```

In my judgment, this issue shouldn't hold up the core-updates-frozen

merge, but it would be nice to improve the out-of-the-box sway experience

in the future. A possible way I see is a sway service type that puts the

necessary configuration in /etc/sway/conf.d or otherwise installs a

session .desktop file that performs the necessary setup.

[0] https://logs.guix.gnu.org/guix/2021-11-22.log#172513

Thoughts?

Jack