Reorganized system call library; uses separate file per call now.

New configuration header file to include/ exclude functionality.
Extracted privileged features from struct proc and create new struct priv.
Renamed various system calls for readability.

kernel/kernel.h

@@ -1,3 +1,6 @@
+#ifndef KERNEL_H
+#define KERNEL_H
+
 /* This is the master header for the kernel.  It includes some other files
  * and defines the principal constants.
  */
@@ -19,8 +22,13 @@
 #include <ibm/portio.h>		/* device I/O and toggle interrupts */ 
 #endif
 
-#include "const.h"		/* kernel constants */
-#include "type.h"		/* kernel type definitions */
-#include "proto.h"		/* kernel function prototypes */
-#include "glo.h"		/* kernel global variables */
+/* Important kernel header files. */
+#include "config.h"		/* configuration, MUST be first */
+#include "const.h"		/* constants, MUST be second */
+#include "type.h"		/* type definitions, MUST be third */
+#include "proto.h"		/* function prototypes */
+#include "glo.h"		/* global variables */
+#include "ipc.h"		/* IPC constants */
+#include "debug.h"		/* debugging, MUST be last kernel header */
 
+#endif /* KERNEL_H */