backend/x11: fix WLR_HAS_XCB_XKB always undefined
+#include <wlr/config.h>
#include <wlr/interfaces/wlr_input_device.h>
#include <wlr/interfaces/wlr_keyboard.h>
#include <wlr/interfaces/wlr_pointer.h>
#elif __FreeBSD__
#include <dev/evdev/input-event-codes.h>
#endif
+#ifdef WLR_HAS_XCB_XKB
+#include <xcb/xkb.h>
+#endif
#include "backend/x11.h"
#include "util/signal.h"
