Linux: Fix build with `dbus=no` or `threads=no`

platform/linuxbsd/detect.py

@@ -336,7 +336,7 @@ def configure(env: "SConsEnvironment"):
         else:
             env.Append(CPPDEFINES=["PULSEAUDIO_ENABLED", "_REENTRANT"])
 
-    if env["dbus"]:
+    if env["dbus"] and env["threads"]:  # D-Bus functionality expects threads.
         if not env["use_sowrap"]:
             if os.system("pkg-config --exists dbus-1") == 0:  # 0 means found
                 env.ParseConfig("pkg-config dbus-1 --cflags --libs")

platform/linuxbsd/wayland/display_server_wayland.cpp

@@ -1535,14 +1535,14 @@ Key DisplayServerWayland::keyboard_get_keycode_from_physical(Key p_keycode) cons
 }
 
 bool DisplayServerWayland::color_picker(const Callable &p_callback) {
+#ifdef DBUS_ENABLED
 	WindowID window_id = MAIN_WINDOW_ID;
 	// TODO: Use window IDs for multiwindow support.
-
 	WaylandThread::WindowState *ws = wayland_thread.wl_surface_get_window_state(wayland_thread.window_get_wl_surface(window_id));
-#ifdef DBUS_ENABLED
 	return portal_desktop->color_picker((ws ? ws->exported_handle : String()), p_callback);
-#endif
+#else
 	return false;
+#endif
 }
 
 void DisplayServerWayland::try_suspend() {

platform/linuxbsd/x11/display_server_x11.cpp

@@ -3628,6 +3628,7 @@ Key DisplayServerX11::keyboard_get_label_from_physical(Key p_keycode) const {
 }
 
 bool DisplayServerX11::color_picker(const Callable &p_callback) {
+#ifdef DBUS_ENABLED
 	WindowID window_id = last_focused_window;
 
 	if (!windows.has(window_id)) {
@@ -3636,6 +3637,9 @@ bool DisplayServerX11::color_picker(const Callable &p_callback) {
 
 	String xid = vformat("x11:%x", (uint64_t)windows[window_id].x11_window);
 	return portal_desktop->color_picker(xid, p_callback);
+#else
+	return false;
+#endif
 }
 
 DisplayServerX11::Property DisplayServerX11::_read_property(Display *p_display, Window p_window, Atom p_property) {