devel/glib20: unbreak session bus autolaunch after fcf0cc114ab8

$ pkg install gtk4
$ service dbus onestart
$ cat /var/lib/dbus/machine-id
123456789012345678901234567890123
$ unset DBUS_SESSION_BUS_ADDRESS XDG_RUNTIME_DIR
$ gtk4-demo
(gtk4-demo:1234): Gtk-WARNING **: Unable to acquire session bus: Cannot spawn a message bus without a machine-id: Unable to load /var/local/lib/dbus/machine-id or /etc/machine-id: Failed to open file “/var/local/lib/dbus/machine-id”: No such file or directory
^C
$ gdbus call --session --dest=org.freedesktop.DBus --object-path=/ --method=org.freedesktop.DBus.ListNames
Error connecting: Cannot spawn a message bus without a machine-id: Unable to load /var/local/lib/dbus/machine-id or /etc/machine-id: Failed to open file “/var/local/lib/dbus/machine-id”: No such file or directory

Reported by: vermaden