bug#48228: json-serialize should signal error when dll is not found [MS Windows]

[Eli Zaretskii]

> Cc: rpluim@gmail.com, p.stephani2@gmail.com, 48228@debbugs.gnu.org
> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Tue, 4 May 2021 20:47:26 +0300
> 
> On 04.05.2021 20:42, Eli Zaretskii wrote:
> > How is that different from similar code that relies on, say, librsvg
> > to display SVG images?
> 
> Does it have a Lisp entry point? If so, I suppose it should be fixed too.

We have create-image, which currently explicitly checks for the
relevant library to be available to Emacs.

> My main experience with librsvg is creating image specs manually and 
> having them used via the 'display' text property. There is no obvious 
> place to signal an error in that scenario.

There is: in create-image.