bug#39662: 28.0.50; Emacs crashes in x_cr_define_fringe_bitmap if (fringe-mode 0)

[Eli Zaretskii]

> From: Robert Pluim <rpluim@gmail.com>
> Date: Tue, 18 Feb 2020 20:32:37 +0100
> Cc: 39662@debbugs.gnu.org, Dmitry Gutov <dgutov@yandex.ru>
> 
> I took another look, signaling is not necessary, we can just make
> define-fringe-bitmap set the width to 1 or some other reasonable value
> if zero is passed in.

The documentation says that WIDTH must be between 1 and 16, so I think
signaling an error is OK.

Btw, the code enforces wider limitations, so it is also OK to fix the
limits, so as to make them consistent with documentation.