always install and look for menus in data dirs
this allows us to work without a populated /etc. as may be the case with modern linux variants, or systemd-sysext'ing kdesrc-builds (i.e. builds getting overlayfs'd into /usr)
this allows us to work without a populated /etc. as may be the case with modern linux variants, or systemd-sysext'ing kdesrc-builds (i.e. builds getting overlayfs'd into /usr)