We need this to run `test-theme`, otherwise when run as part of the
build tests it fails like:
error while loading shared libraries: libmutter-cogl-4.so.0: cannot
open shared object file: No such file or directory
https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/442
sources: st_gir_sources + st_non_gir_sources,
c_args: st_cflags,
dependencies: [clutter_dep, gtk_dep, croco_dep, x11_dep, m_dep],
+ build_rpath: mutter_typelibdir,
install_rpath: mutter_typelibdir,
install_dir: pkglibdir,
install: true