. load average calculation changed to calculate it all over every tick

instead of keeping a running total of enqueued processes
   (because somehow the load average was broken)
 . added SI_KPROC_TAB to get a copy of kernel process table from PM, for
   a top implementation
 . fixed arg to sys_nice() to make it an endpoint, not a slot number

include/minix/type.h

@@ -121,7 +121,6 @@ struct kinfo {
 
 /* Runnable processes and other load-average information. */
 struct loadinfo {
-  u16_t procs_enqueued;		/* current no. of runnable processes */
   u16_t proc_load_history[_LOAD_HISTORY];	/* history of proc_s_cur */
   u16_t proc_last_slot;
   clock_t last_clock;

include/unistd.h

@@ -46,6 +46,7 @@
 #define SI_MEM_ALLOC	   4	/* get memory allocation data */
 #define SI_DATA_STORE	   5	/* get copy of data store */
 #define SI_LOADINFO	   6	/* get copy of load average structure */
+#define SI_KPROC_TAB	   7	/* copy of kernel process table */
 
 /* NULL must be defined in <unistd.h> according to POSIX Sec. 2.7.1. */
 #define NULL    ((void *)0)