convert timespec structures to timeval and vice versa.

timeconv.h

#ifndef TIMEVAL_TO_TIMESPEC
#define  TIMEVAL_TO_TIMESPEC(tv, ts)	      \
	do {                                      \
		(ts)->tv_sec = (tv)->tv_sec;          \
		(ts)->tv_nsec = (tv)->tv_usec * 1000; \
	} while (0)
#endif
#ifndef TIMESPEC_TO_TIMEVAL
#define	TIMESPEC_TO_TIMEVAL(tv, ts)           \
	do {								      \
		(tv)->tv_sec = (ts)->tv_sec;          \
		(tv)->tv_usec = (ts)->tv_nsec / 1000; \
	} while (0)
#endif