bug#47832: 28.0.50; define-fringe-bitmap and emacs --daemon

[Gregory Heytings]

> > There are three kind of bitmaps:
> >
> > 1. standard bitmaps not overridden by user-defined bitmaps
> > 2. standard bitmaps overridden by user-defined bitmaps
> > 3. user-defined bitmaps
> >
> > The first loop processes the bitmaps of the first kind, the second loop 
> > the bitmaps of the second and third kind.
>
> I'm asking why do we need to process the second kind here.  That kind 
> was already set up when user initializations defined replacements for 
> those standard bitmaps.  Right?  So why do we need to set them up again?

What you write is correct when you call "emacs", not when you call "emacs 
--daemon".  In the latter case the user-defined bitmaps have not yet been 
set up.  It's explained in the comment:

   /* Set up user-defined fringe bitmaps that might have been defined
      before the frame of this kind was initialized.  This can happen
      if Emacs is started as a daemon and the init files define fringe
      bitmaps.  */

The code was written under the erroneous assumption that there are only 
two kind of bitmaps: standard bitmaps and user-defined bitmaps.  Hence the 
bug that this patch fixes.