KTRACE
#define KTRACE() kprintf("%s %d\n", __FILE__, __LINE__)
#define KTRACE()
# define KTRACE(format...) ktrace_printf(format)
# define KTRACE(format...)
# define KTRACE(format...) ktrace_printf(format)
# define KTRACE(format...) ;
# define KTRACE(x...) ktrace_printf(x)
# define KTRACE(x...) do {} while (false)
# define KTRACE(format...) ktrace_printf(format)
# define KTRACE(format...) do {} while (false)
# define KTRACE(x...) ktrace_printf(x)
# define KTRACE(x...)