gnome-shell now includes a light variant, and supports switching
between dark- and light styling at runtime.
That means we no longer have to build our own stylesheet, and can
instead just instruct gnome-shell to always use the light style
in the classic session.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell-extensions/-/merge_requests/254>
The regular GNOME session ships with three options:
* GNOME
* GNOME on Wayland (available when GDM starts in X11)
* GNOME on Xorg (available when GDM starts in Wayland)
The main GNOME session is set up so it works to match how GDM starts,
so GNOME is on Wayland if GDM is (or GNOME is on X11 if GDM is).
For GNOME Classic, we are missing this setup, so port this behavior
over from the GNOME session setup.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell-extensions/-/merge_requests/195>
We follow the rule of not putting generated files under version
control, but that means drawing in additional build-time dependencies.
We can reduce those when building from a released tarball by
generating the stylesheets at dist time though, so do that.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell-extensions/-/merge_requests/150>