Incompatible change of update-file-autoloads function

[Yasuhiro KIMURA]

Hello,

I updated emacs to current HEAD of master branch and found build of a
certain 3rd party application fails with following code.

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(defun lookup-autoload ()
  (require 'autoload)
  (setq generated-autoload-file
        (expand-file-name "lookup-autoloads.el" default-directory)
        backup-enable-predicate 'ignore)
  (mapc (lambda (file)
          (update-file-autoloads file t))
        command-line-args-left))
----------------------------------------------------------------------

I did bisect test and found the error happens after following commit.

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commit 6f36b67e4146ef4610916b7903fd292e1308daf5
Author: Lars Ingebrigtsen <larsi@gnus.org>
Date:   Fri Oct 2 04:34:31 2020 +0200

    Stop using a dynamically bound 'generated-autoload-file' variable

    * doc/lispref/loading.texi (Autoload): Document change of name
    (bug#39823).

    * lisp/emacs-lisp/autoload.el (autoload-find-generated-file): Pass
    the file name in.
    (autoload-generated-file): Ditto.
    (autoload-file-load-name): Ditto.
    (generate-file-autoloads): Ditto.
    (autoload--setup-output): Ditto.
    (autoload-generate-file-autoloads): Ditto, and alter doc string to
    reflect when `generated-autoload-file' is heeded.
    (update-file-autoloads): Pass outfile in to functions.
    (autoload-find-destination): Ditto.
    (update-directory-autoloads): Make into an obsolete shim around
    `make-directory-autoloads'.
    (make-directory-autoloads): Renamed from
    `update-directory-autoloads' with new semantics.
    (batch-update-autoloads): Adjust caller.

    * lisp/emacs-lisp/package.el (package-generate-autoloads): Adjust
    caller.
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According to commit message update-file-autoloads function seems to
change incompatibly.

Then is there any way to make above lookup-autoload function work fine
with both before and after this commit?

Best Regards.

---
Yasuhiro KIMURA