TRACE
#define TRACE BIT(4) /* var: user flagged, func: execution tracing */
#define TRACE() xprintf("TRACE %s:%d\n", __FILE__, __LINE__)
#define TRACE(x) printf x
#define TRACE(x)
#define TRACE(n, fmt...) do { \
#define TRACE(n, fmt, ...) do { } while (0)
#define TRACE -4
#define TRACE(l, x) if ((l) <= dbg) printf x