+#ifndef NO_LIBSYSTEMD
+# include <systemd/sd-bus.h>
+# include <systemd/sd-bus-protocol.h>
+#else
+ struct sd_bus;
+# define sd_bus_default_user(p) ((*(p)=NULL),(-ENOTSUP))
+# define sd_bus_default_system(p) ((*(p)=NULL),(-ENOTSUP))
+# define sd_bus_call_method(...) (-ENOTSUP)
+#endif