bug#1990: 23.0.60; Emacs trying too hard to find fonts that don't exist

[Jason Rumney]

Chong Yidong wrote:
> At the end of fontset_font (fontset.c:699), there is the following code:
>
>   /* Remeber that we have no font for C.  */
>   FONTSET_SET (fontset, make_number (c), Qt);
>
>   return Qnil;
>
> However, there are several other places in that function that return
> with a Qnil, without doing this FONTSET_SET.  Do matters improve if we
> do the same FONTSET_SET call before returning?
>   

It doesn't seem to help much, if at all.

Looking at those other locations, nil is only returned when some other 
function returns t, indicating that it already remembers that we have no 
font.