bug#30203: 25.3; without-xft fonts don't properly inherit from default face

[Eli Zaretskii <eliz@gnu.org>]

> From: talchas@talchas.net
> Date: Sun, 21 Jan 2018 21:23:20 -0800
> 
> When built without xft, faces that specify weight such as bold don't
> take their family from the default face if it doesn't match weight.
> 
> You can see this with:
> emacs -Q
> (set-frame-font "-xos4-terminus-medium-r-normal--14-*-72-72-c-80-iso10646-1")
> 
> and look at the mode line buffer display - on my system it is
> -misc-fixed-... according to dump-face. This still occurs on git HEAD
> (b3fb0d47c158cb0d1acdce5008628e1d1a337bbb) as well as the system 25.3 below.
> 
> When built with xft this does not occur (still selected via the X font
> name), and neither does it on 24.5. The proximate cause of the
> regression appears to be bf0d3f76dcfe7881cb3058169b51cf6602fdcdcb,
> reversing the
> 
> -	  = font_load_for_lface (f, attrs, attrs[LFACE_FONT_INDEX]);
> +	  = font_load_for_lface (f, attrs, Ffont_spec (0, NULL));
> 
> gives the old behavior despite --without-xft. Given that xft is fine
> on 25.3, there presumably is some more correct fix to font selection.

That change was made to fix two bugs, whose numbers are mentioned in
the log entry and in the discussion of the bug.  Can you try
reproducing those bugs in the build without xft?  If those bugs only
happen with xft, then the fix is easy.  Otherwise, we will have to
investigate more thoroughly.

Thanks.