bug#56896: 29.0.50; [PATCH] Make the bookmark fringe icon look like a bookmark

[Jim Porter]

On 8/2/2022 12:18 PM, Eli Zaretskii wrote:
> Why not make the icon customizable, and offer several possible bitmaps
> to chose from?  Hardcoding a single icon will always annoy someone.

Sure, we could make this customizable. What would be a good way to go 
about this? I see three options:

1) The status quo: users can already call (define-fringe-bitmap 
'bookmark-fringe-bitmap ...) to make the icon whatever they like, though 
that obviously requires writing (or copy/pasting) Elisp.

2) Let `bookmark-set-fringe-mark' take a symbol for a bitmap to use for 
the mark (it currently takes a boolean). This would solve this immediate 
case, but not other similar cases. For example, what if a user wants to 
customize the fringe icons in diff-mode?

3) Provide a generic way to select what any fringe bitmap looks like. 
I'm not quite sure how this would be implemented, but it would then 
allow users to change the appearance of, say, the `left-curly-arrow' 
icon. (In the past, I've done this via (1) by just calling 
`define-fringe-bitmap' again.)