On my system, without systemd, the date-and-time panel crashes
gnome-control-center when I try to open it.

Attaching a naive patch that gives me a running panel, although of
course it does not do anything.

This is the trace:

GLib-CRITICAL **: g_str_has_prefix: assertion `str != NULL' failed

GLib-CRITICAL **: g_str_has_prefix: assertion `str != NULL' failed

Program received signal SIGSEGV, Segmentation fault.
0xb754c41b in ?? () from /lib/i386-linux-gnu/i686/cmov/libc.so.6
(gdb) bt
0  0xb754c41b in ?? () from /lib/i386-linux-gnu/i686/cmov/libc.so.6
1  0xb7606d03 in g_str_equal (v1=0x0, v2=0xaba7a6bc) at ghash.c:1704
2  0xaba76d2c in compare_timezones (b=0xaba7a6bc "Asia/Istanbul", a=0x0) at tz.c:294
3  tz_info_get_clean_name (tz_db=0x8328ff0, tz=0x0) at tz.c:329
4  0xaba75f1c in cc_timezone_map_set_timezone (map=0x81b1b20, timezone=0x0) at cc-timezone-map.c:584
5  0xaba72d85 in get_initial_timezone (self=0x828f490) at cc-datetime-panel.c:561
6  0xaba74aa6 in cc_date_time_panel_init (self=0x828f490) at cc-datetime-panel.c:1063
7  0xb771ea7b in g_type_create_instance (type=136370936) at gtype.c:1892
8  0xb7701528 in g_object_constructor (type=136370936, n_construct_properties=2, construct_params=0x82e73f8) at gobject.c:1839
9  0xb7702d69 in g_object_newv (object_type=136370936, n_parameters=2, parameters=0x82e7270) at gobject.c:1703
10 0xb77035c3 in g_object_new_valist (object_type=136370936, first_property_name=0x8054681 "shell", var_args=0xbfffe6b8 "\006") at gobject.c:1820
11 0xb7703820 in g_object_new (object_type=136370936, first_property_name=0x8054681 "shell") at gobject.c:1535
12 0x0804fb33 in activate_panel (gicon=0x81cce78, name=0x82f2b08 "Fecha y hora", desktop_file=<optimized out>, argv=0x0, id=0x82e33d0 "datetime", 
   shell=0x80c7c28) at gnome-control-center.c:159
13 _shell_set_active_panel_from_id (shell=0x80c7c28, start_id=0x82e33d0 "datetime", argv=0x0, err=0xbfffe75c) at gnome-control-center.c:911
14 0x0804ea51 in item_activated_cb (view=0x81ed2d0, name=0x82e7218 "Fecha y hora", id=0x82e33d0 "datetime", 
   desktop_file=0x82f1bb0 "/home/diego/gnome/build/share/applications/gnome-datetime-panel.desktop", shell=0x80c7c28) at gnome-control-center.c:263
15 0xb76fd5bc in g_closure_invoke (closure=0x821d358, return_value=0x0, n_param_values=4, param_values=0x827ed48, invocation_hint=0xbfffe870)
   at gclosure.c:774
16 0xb770eb05 in signal_emit_unlocked_R (node=0x81fac28, detail=0, instance=0x81ed2d0, emission_return=0x0, instance_and_params=0x827ed48) at gsignal.c:3302
17 0xb7716682 in g_signal_emit_valist (instance=0x81ed2d0, signal_id=206, detail=0, var_args=0xbfffea28 "\002") at gsignal.c:3033
18 0xb7716813 in g_signal_emit (instance=0x81ed2d0, signal_id=206, detail=0) at gsignal.c:3090
19 0x08051af4 in iconview_item_activated_cb (icon_view=0x81ed2d0, path=0x8228c60, cc_view=0x81ed2d0) at cc-shell-item-view.c:143
20 0xb76ff68a in g_cclosure_marshal_VOID__BOXED (closure=0x822f368, return_value=0x0, n_param_values=2, param_values=0x8279990, invocation_hint=0xbfffebb0, 
   marshal_data=0x0) at gmarshal.c:574
21 0xb76fd5bc in g_closure_invoke (closure=0x822f368, return_value=0x0, n_param_values=2, param_values=0x8279990, invocation_hint=0xbfffebb0)
   at gclosure.c:774
22 0xb770eb05 in signal_emit_unlocked_R (node=0x81f91d8, detail=0, instance=0x81ed2d0, emission_return=0x0, instance_and_params=0x8279990) at gsignal.c:3302
23 0xb7716682 in g_signal_emit_valist (instance=0x81ed2d0, signal_id=198, detail=0, 
   var_args=0xbfffed60 "\320\322\036\b\300\212\"\b@w\037\b\241\033\005\b\320\322\036\b\240\214\"\b\320\322\036\b\360\271o\267p\257\006\bH")
   at gsignal.c:3033
24 0xb7716813 in g_signal_emit (instance=0x81ed2d0, signal_id=198, detail=0) at gsignal.c:3090
25 0xb7c68faa in gtk_icon_view_item_activated (icon_view=0x81ed2d0, path=0x8228ca0) at gtkiconview.c:5381
26 0x08051ba1 in iconview_button_release_event_cb (cc_view=0x81ed2d0, widget=<optimized out>, event=<optimized out>) at cc-shell-item-view.c:111
27 iconview_button_release_event_cb (widget=0x81ed2d0, event=0x81ee068, cc_view=0x81ed2d0) at cc-shell-item-view.c:95
28 0xb7c901ba in _gtk_marshal_BOOLEAN__BOXED (closure=0x8231628, return_value=0xbfffeef4, n_param_values=2, param_values=0x8279800, 
   invocation_hint=0xbfffeee0, marshal_data=0x0) at gtkmarshalers.c:85
29 0xb76fd5bc in g_closure_invoke (closure=0x8231628, return_value=0xbfffeef4, n_param_values=2, param_values=0x8279800, invocation_hint=0xbfffeee0)
   at gclosure.c:774
30 0xb770eb05 in signal_emit_unlocked_R (node=0x806a960, detail=0, instance=0x81ed2d0, emission_return=0xbffff02c, instance_and_params=0x8279800)
   at gsignal.c:3302
31 0xb77165a7 in g_signal_emit_valist (instance=0x81ed2d0, signal_id=29, detail=0, 
   var_args=0xbffff090 "\274\360\377\277h\340\036\b\320\322\036\b\263\256\336\267\320\322\036\b\250[\006\b") at gsignal.c:3043
32 0xb7716813 in g_signal_emit (instance=0x81ed2d0, signal_id=29, detail=0) at gsignal.c:3090
33 0xb7deb093 in gtk_widget_event_internal (widget=0x81ed2d0, event=0x81ee068) at gtkwidget.c:6154
34 0xb7c8f8f2 in gtk_propagate_event (widget=0x81ed2d0, event=0x81ee068) at gtkmain.c:2420
35 0xb7c8fd80 in gtk_main_do_event (event=0x81ee068) at gtkmain.c:1687
36 0xb7a8a53c in _gdk_event_emit (event=0x81ee068) at gdkevents.c:71
37 0xb7ab84e8 in gdk_event_source_dispatch (source=0x8095258, callback=0, user_data=0x0) at gdkeventsource.c:360
38 0xb761699a in g_main_dispatch (context=0x80968f0) at gmain.c:2510
39 g_main_context_dispatch (context=0x80968f0) at gmain.c:3047
40 0xb7616da5 in g_main_context_iterate (dispatch=1, block=-1218296320, context=0x80968f0, self=<optimized out>) at gmain.c:3118
41 g_main_context_iterate (context=0x80968f0, block=-1218296320, dispatch=1, self=<optimized out>) at gmain.c:3055
42 0xb7616e81 in g_main_context_iteration (context=0x80968f0, may_block=1) at gmain.c:3179
43 0xb77de09c in g_application_run (application=0x8191568, argc=1, argv=0xbffff3d4) at gapplication.c:1493
44 0x0804e44b in main (argc=1, argv=0xbffff3d4) at control-center.c:199