Userspace shouldn't (and doesn't seem to) need machine/pcb.h.

Unfortunately the file is included by loads of stuff, mostly in
src/external, so can't be killed outright.

sys/sys/user.h

@@ -1,4 +1,4 @@
-/*	$NetBSD: user.h,v 1.18 2011/01/14 02:06:34 rmind Exp $	*/
+/*	$NetBSD: user.h,v 1.19 2014/02/19 20:40:40 dsl Exp $	*/
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1991, 1993
@@ -38,10 +38,4 @@
 #error "This header has been obsoleted and will be removed."
 #endif
 
-#include <machine/pcb.h>
-
-struct user {
-	struct pcb u_pcb;
-};
-
 #endif /* !_SYS_USER_H_ */