various coverity-inspired fixes

. some strncpy/strcpy to strlcpy conversions
	. new <minix/param.h> to avoid including other minix headers
	  that have colliding definitions with library and commands code,
	  causing parse warnings
	. removed some dead code / assignments

kernel/proc.c

@@ -30,11 +30,9 @@
  */
 
 #include <minix/com.h>
-#include <minix/endpoint.h>
 #include <minix/ipcconst.h>
 #include <stddef.h>
 #include <signal.h>
-#include <minix/syslib.h>
 #include <assert.h>
 
 #include "debug.h"
@@ -47,6 +45,8 @@
 
 #include "arch_proto.h"
 
+#include <minix/syslib.h>
+
 /* Scheduling and message passing functions */
 static void idle(void);
 /**