ref: 37f5a0e48ea1a65d4bed95f4e29a2ea9a3b81356
dir: /sys/src/ape/lib/ap/gen/clock.c/
#include <time.h>
#include <sys/times.h>
clock_t
clock(void)
{
	struct tms t;
	if(times(&t) == (clock_t)-1)
		return (clock_t)-1;
	return t.tms_utime+t.tms_stime;
}