gnome-shell hardcodes a vertical one-column workspace layout, and
while not supporting arbitrary grids is very much by design, it
currently doesn't have a choice: We simply don't expose the workspace
layout we use.
Change that to allow gnome-shell to be a bit more flexible with the
workspace layouts it supports.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/618
The order and way include macros were structured was chaotic, with no
real common thread between files. Try to tidy up the mess with some
common scheme, to make things look less messy.
meta_workspace_manager_override_workspace_layout is implemented by
calling meta_workspace_manager_update_workspace_layout which
respects the workspace_layout_overridden flag. After the first call
to meta_workspace_manager_override_workspace_layout all subsequent
calls fail silently.
Reset workspace_layout_overridden to FALSE before calling
meta_workspace_manager_update_workspace_layout.
https://gitlab.gnome.org/GNOME/mutter/issues/270
