implement the remaining clock_* interfaces

src/time/clock_getcpuclockid.c

+#include <time.h>
+#include <errno.h>
+#include <unistd.h>
+#include "syscall.h"
+
+int clock_getcpuclockid(pid_t pid, clockid_t *clk)
+{
+	if (pid && pid != getpid()) return EPERM;
+	*clk = CLOCK_PROCESS_CPUTIME_ID;
+	return 0;
+}

src/time/clock_getres.c

+#define SYSCALL_RETURN_ERRNO
+#include <time.h>
+#include "syscall.h"
+
+int clock_getres(clockid_t clk, struct timespec *ts)
+{
+	return syscall2(__NR_clock_getres, clk, (long)ts);
+}

src/time/clock_gettime.c

+#define SYSCALL_RETURN_ERRNO
 #include <time.h>
 #include "syscall.h"
 

src/time/clock_nanosleep.c

+#define SYSCALL_RETURN_ERRNO
+#include <time.h>
+#include "syscall.h"
+
+int clock_nanosleep(clockid_t clk, int flags, const struct timespec *req, struct timespec *rem)
+{
+	return syscall4(__NR_clock_nanosleep, clk, flags, (long)req, (long)rem);
+}

src/time/clock_settime.c

+#define SYSCALL_RETURN_ERRNO
+#include <time.h>
+#include "syscall.h"
+
+int clock_settime(clockid_t clk, const struct timespec *ts)
+{
+	return syscall2(__NR_clock_settime, clk, (long)ts);
+}