CDEBUG
#define CDEBUG(l, f, s) if (Debug >= l) fprintf(stderr, f, s)
#define CDEBUG(l, f, s)
#define CDEBUG(l, f, s) if (Debug >= l) (void)fprintf(stderr, f, s)
#define CDEBUG(l, f, s)
#define CDEBUG(l, f, s)