#include <u.h>#include <libc.h> voidmain(int, void**){	uvlong n, t, s; 	s = nsec();	print("start nanoseconds %zd\n", s);	for(n = 0; n<1000*1000*1000; n++){		;	}	print("n %zd\n", n);	t = nsec();	print("end   nanoseconds %zd taken %zd\n", t, t -s);	exits(0);}