anchor.diff:  (defun to-lap (backend-function)
     (multiple-value-bind (uses defs)
         (mezzano.compiler.backend::build-use/def-maps backend-function)
  -    (multiple-value-bind (*stack-layout* debug-layout)
  +    (multiple-value-bind (*stack-layout* debug-layout environment-slot)
           (compute-stack-layout backend-function uses defs)
         (let ((*saved-multiple-values* (make-hash-table))
               (*dx-root-visibility* (make-hash-table))
  
positive.code:                           (not (getf (sys.c:lexical-variable-plist ast)
                                       'sys.c::hide-from-debug-info)))
                  do (push (list (sys.c::lexical-variable-name ast) slot) debug-layout))))
        (values (make-array (length layout)
                            :adjustable t
                            :fill-pointer t
                            :initial-contents layout)
                debug-layout))))
  
  (defun allocate-stack-slots (count &key (livep t) aligned)
    (assert (not *current-frame-layout*) ()
  
negative.code:     (sys.int::assemble-lap
       lap
       (backend-function-name backend-function)
       (let* ((ast-lambda (mezzano.compiler.backend::ast backend-function)))
         (list :debug-info
               (backend-function-name backend-function) ; name
               debug-layout ; local variable stack positions
               ;; Environment index
               environment-slot
               ;; Environment layout
               (second (sys.c:lambda-information-environment-layout ast-lambda))
               ;; Source file
               (if *compile-file-pathname*
                   (namestring *compile-file-pathname*)
                   nil)
               ;; Top-level form number
               sys.int::*top-level-form-number*
               (sys.c:lambda-information-lambda-list ast-lambda) ; lambda-list
               (sys.c:lambda-information-docstring ast-lambda))) ; docstring
       nil
       :x86-64)))
  
  