Backtrace apply frames have 1st arg duplicated

[Neil Jerram]

Hi there, please note the occurrences of `#t #t' in the following.

address@hidden:~/SW/Guile/git$ meta/guile -q
Guile Scheme interpreter 0.5 on Guile 1.9.3
Copyright (C) 2001-2008 Free Software Foundation, Inc.

Enter `,help' for help.
scheme@(guile-user)> (define s (make-stack #t))
scheme@(guile-user)> (display-backtrace s (current-output-port))
In system/vm/vm.scm:
  41: 0* [vm-load #<vm 84df8f0> #<objcode 87892a0>]
In unknown file:
   ?: 1* [#<vm 84df8f0> #<program 8789270 at standard input:0:0 ()>]
In standard input:
   1: 2* [#<program 8789270 at standard input:0:0 ()>]
In unknown file:
   ?: 3* [make-stack #t #t]
scheme@(guile-user)> (frame-arguments (stack-ref s 0))
(#t #t)

The make-stack frame should say just `[make-stack #t]'.

I would guess this problem was introduced by your cclo->gsubr changes,
beginning at e20d7001c3f7150400169fecb0bf0eefdf122fe2.  I don't mind
debugging it, but maybe the problem is obvious to you, now I've pointed
it out?

Here's a test, anyway.

  (let ((s (make-stack #t)))
    (= (length (frame-arguments (stack-ref s 0))) 1))

Regards,
        Neil