- enable ipc warnings by default

- ipc checking code in kernel didn't properly catch the
   sendrec() to self case; added special case check
 - triggered by PM using stock panic() - needs its own _exit()

reported by Joren l'Ami.

servers/pm/forkexit.c

@@ -417,3 +417,13 @@ register struct mproc *rmp;	/* tells which process is exiting */
   rmp->mp_child_stime = 0;
   procs_in_use--;
 }
+
+PUBLIC void _exit(int code)
+{
+	sys_exit(SELF);
+}
+
+PUBLIC void __exit(int code)
+{
+	sys_exit(SELF);
+}