>>>> This attached alternate patch introduces two new compatibility macros
>>>> named `org-flet' and `org-labels' in org-macs.el.  These macros are
>>>> aliased to the appropriate cl macro depending on the version of Emacs in
>>>> use.
>>> This is interesting, but seems not fully functional. After applying
>>> patch I tried export to html but got
>
>>> Symbol's function definition is void: matches
>
>>> I'll compare your and mine patches later.
>
>> I found the source of that message, in my patch I use `cl-flet*' for
>> `ob.el' (around lines 1264). I don't remember exactly why star version
>> is needed but it works.
>

Okay, I've noticed a number of these errors as well.  It looks like the
old version of flet allowed the definition of recursive functions, but
the new cl-flet does not.

Below find my previous patch which now uses cl-flet* instead of cl-flet
in org-flet.  This should be a universal fix.

Best,