compositor-{drm, fbdev, rpi}: Make VT switching configurable

Add a new boolean weston.ini option, "vt-switching" to enable or
disable Ctrl-Alt-Fn key combinations.

Signed-off-by: Bob Ham <bob.ham@collabora.com>
Reviewed-by: Derek Foreman <derekf@osg.samsung.com>

(Derek Foreman changed the prototype for switch_vt_binding to
have a weston_keyboard * instead of weston_seat *.  The pointer
wasn't used, so this is just a warning fix.)
diff --git a/src/main.c b/src/main.c
index 6d2216f..1850fa6 100644
--- a/src/main.c
+++ b/src/main.c
@@ -499,6 +499,7 @@
 	struct xkb_rule_names xkb_names;
 	struct weston_config_section *s;
 	int repaint_msec;
+	int vt_switching;
 
 	s = weston_config_get_section(config, "keyboard", NULL, NULL);
 	weston_config_section_get_string(s, "keymap_rules",
@@ -520,6 +521,10 @@
 	weston_config_section_get_int(s, "repeat-delay",
 				      &ec->kb_repeat_delay, 400);
 
+	weston_config_section_get_bool(s, "vt-switching",
+				       &vt_switching, true);
+	ec->vt_switching = vt_switching;
+
 	s = weston_config_get_section(config, "core", NULL, NULL);
 	weston_config_section_get_int(s, "repaint-window", &repaint_msec,
 				      ec->repaint_msec);