tools/toolbox: Install sysext dependencies if necessary
While the toolbox image itself has all necessary dependencies to
build and run the shell, we still need them in the destdir when
building a system extension.
Achieve this by running .gitlab-ci/install-common-dependencies.sh
if it exists, which is the script that is used both for gnome-os
system extensions and mutter's CI image.
projects / gnome-shell.git / commit