bug#70007: [PATCH] native JSON encoder

[Eli Zaretskii]

> From: Mattias Engdegård <mattias.engdegard@gmail.com>
> Date: Sat, 30 Mar 2024 15:22:34 +0100
> Cc: casouri@gmail.com,
>  70007@debbugs.gnu.org
> 
> I made the changes above and installed it on master, as well as a sweeping 
> removal of all things Jansson.

Thanks.  The new code failed to link due to an omission in
src/Makefile.in, and also the "clever" initialization in
json_serialize confused make-docfile (so globals.h were generated
incorrectly: they missed the DEFSYMs in syms_of_json).  I think I
fixed that, but please eyeball the changes to see if I missed
something.