bug#59347: 29.0.50; `:family` face setting ignored

[Gregory Heytings]

> > Okay, now I see what you mean.  It is not self-evident indeed, it is 
> > the intended behavior that is visible (or at least that I see) in the 
> > existing code
>
> Well, you just explained in so many words why some of the existing code 
> is wrong in your opinion, so arguments based on the existing code are 
> not very convincing...

;-)  The fact that there is a bug in the current code doesn't mean that 
its general structure (and in this case the meaning and intent of 
font_find_for_lface) is not visible.  But I may very well misunderstand 
that structure, or see things that are in fact not visible.

> > emacs -Q -fn 'Sans Serif-12:slant=oblique:width=condensed'
> >
> > works as expected and behaves like Emacs 28: the font for the default 
> > face is a condensed and oblique variable-pitch sans serif font.
>
> And the size is indeed 12?

I think so, yes.  The size is different with -10, -11, -12, -13, -14. 
With -12 on my computer I get the x:-urw-nimbus sans 
l-regular-i-condensed--32-231-100-100-p-144-iso8859-1 font.

> I suggest to describe the default value in the doc string, since 
> gleaning that from a (decimal) value displayed by Emacs by default is 
> not that easy.  Maybe also add a sentence which explains why that is the 
> default.

Okay, I'll do that.  Should I post the updated version of the patch before 
pushing?