Update some other copyright years automatically, by running:
Run 'UPDATE_COPYRIGHT_YEAR=2019 \
UPDATE_COPYRIGHT_USE_INTERVALS=1 \
UPDATE_COPYRIGHT_MAX_LINE_LENGTH=79 admin/update-copyright'
followed by 'admin/merge-gnulib'.
* lisp/emacs-lisp/cconv.el (cconv--convert-funcbody): New function.
(cconv--convert-function): Extracted from here.
(cconv-convert): Also use it here, in the lambda lifted case, so that
mutated args are properly accounted for.
* test/lisp/emacs-lisp/cconv-tests.el: New test.