bug#41946: 27.0.91; native json parsing: add :empty-object configuration

[Dmitry Gutov]

On 04.08.2021 08:55, Lars Ingebrigtsen wrote:
> The user didn't want to rewrite the code to alter some conditionals, and
> instead wanted Emacs to be changed so that they didn't have to do that.
> I pointed out that the user can trivially just pre-process the data if
> they didn't want to rewrite those conditionals.

It's not like the request is illogical (empty object can also be 
conflated with empty array if json-array-type is 'list'), or it would 
take much effort to implement.

I don't have the time to work on this now, though, so I concede to 
whatever is decided here.