deprecate the-last-stack

* libguile/backtrace.h (scm_the_last_stack_fluid_var)
* libguile/backtrace.c (scm_init_backtrace): No more
  scm_the_last_stack_fluid_var. The replacement is to resolve
  `the-last-stack' in (ice-9 stack-catch).
  (scm_backtrace_with_highlights): Accordingly, instead of backtracing
  the last stack, backtrace the current stack.

* libguile/throw.h:
* libguile/throw.c:
* libguile/deprecated.h:
* libguile/deprecated.c (scm_internal_stack_catch): Deprecate this
  function.

* module/ice-9/save-stack.scm (the-last-stack): Move here from boot-9.

* module/ice-9/debug.scm:
* module/ice-9/debugger.scm: Use (ice-9 save-stack) for the-last-stack.

* module/ice-9/deprecated.scm (the-last-stack): Add deprecated shim.

module/ice-9/debug.scm

@@ -1,4 +1,4 @@
-;;;; 	Copyright (C) 1996, 1997, 1998, 1999, 2001, 2006 Free Software Foundation
+;;;; 	Copyright (C) 1996, 1997, 1998, 1999, 2001, 2006, 2010 Free Software Foundation
 ;;;; 
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -20,7 +20,8 @@
 
 
 (define-module (ice-9 debug)
-  :export (frame-number->index trace untrace trace-stack untrace-stack))
+  #:use-module (ice-9 save-stack)
+  #:export (frame-number->index trace untrace trace-stack untrace-stack))
 
 
 ;;; {Misc}

module/ice-9/debugger.scm

@@ -22,6 +22,7 @@
   #:use-module (ice-9 debugger utils)
   #:use-module (ice-9 debugging traps)
   #:use-module (ice-9 scm-style-repl)
+  #:use-module (ice-9 save-stack)
   #:use-module (ice-9 format)
   #:export (debug-stack
 	    debug

module/ice-9/deprecated.scm

@@ -61,6 +61,7 @@
             default-pre-unwind-handler
             handle-system-error
             stack-saved?
+            the-last-stack
             save-stack)
 
   #:replace (module-ref-submodule module-define-submodule!))
@@ -654,6 +655,16 @@ the `(system repl common)' module.")
         (identifier? #'id)
         #'(@ (ice-9 save-stack) stack-saved?))))))
 
+(define-syntax the-last-stack
+  (lambda (x)
+    (issue-deprecation-warning
+     "`the-last-stack' is deprecated. Use it from `(ice-9 save-stack)'
+if you need it.")
+    (syntax-case x ()
+      (id
+       (identifier? #'id)
+       #'(@ (ice-9 save-stack) the-last-stack)))))
+
 (define (save-stack . args)
   (issue-deprecation-warning
    "`save-stack' is deprecated. Use it from `(ice-9 save-stack)' if you need

module/ice-9/save-stack.scm

@@ -32,11 +32,14 @@
 (define-module (ice-9 save-stack)
   ;; Replace deprecated root-module bindings, if present.
   #:replace (stack-saved?
+             the-last-stack
              save-stack))
 
 ;; FIXME: stack-saved? is broken in the presence of threads.
 (define stack-saved? #f)
 
+(define the-last-stack (make-fluid))
+
 (define (save-stack . narrowing)
   (if (not stack-saved?)
       (begin