libc: add adjtime() system call.

Implement the adjtime() system call and add a test for it to test69.
Additionally, install the adjtime.2 and clock_*.2 man pages.

servers/pm/param.h

@@ -31,6 +31,7 @@
 #define svrctl_argp	m2_p1
 #define stime      	m2_l1
 #define clk_id		m2_i1
+#define settime_now	m2_i2
 #define time_sec	m2_l1
 #define time_nsec	m2_l2
 #define memsize      	m4_l1

servers/pm/time.c

@@ -76,7 +76,8 @@ int do_settime()
 
   switch (m_in.clk_id) {
 	case CLOCK_REALTIME:
-		s= sys_settime(1, m_in.clk_id, m_in.time_sec, m_in.time_nsec);
+		s= sys_settime(m_in.settime_now, m_in.clk_id, m_in.time_sec,
+							m_in.time_nsec);
 		return(s);
 	case CLOCK_MONOTONIC: /* monotonic cannot be changed */
 	default: