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

[talchas]

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.






In GNU Emacs 25.3.1 (x86_64-pc-linux-gnu, GTK+ Version 3.22.19)
 of 2018-01-16 built on nights-beautiful-daughter
Windowing system distributor 'The X.Org Foundation', version 11.0.11905000
System Description:     NAME=Gentoo

Configured using:
 'configure --prefix=/usr --build=x86_64-pc-linux-gnu
 --host=x86_64-pc-linux-gnu --mandir=/usr/share/man
 --infodir=/usr/share/info --datadir=/usr/share --sysconfdir=/etc
 --localstatedir=/var/lib --disable-dependency-tracking
 --disable-silent-rules --docdir=/usr/share/doc/emacs-25.3
 --htmldir=/usr/share/doc/emacs-25.3/html --libdir=/usr/lib64
 --program-suffix=-emacs-25 --infodir=/usr/share/info/emacs-25
 --localstatedir=/var
 --enable-locallisppath=/etc/emacs:/usr/share/emacs/site-lisp
 --with-gameuser=:gamestat --without-compress-install
 --with-file-notification=inotify --enable-acl --without-dbus
 --without-modules --without-gpm --without-hesiod --without-kerberos
 --without-kerberos5 --with-xml2 --without-selinux --with-gnutls
 --without-wide-int --with-zlib --with-sound=alsa --with-x --without-ns
 --without-gconf --without-gsettings --with-toolkit-scroll-bars
 --with-gif --with-jpeg --with-png --with-rsvg --with-tiff --with-xpm
 --without-imagemagick --without-xft --without-cairo --without-libotf
 --without-m17n-flt --with-x-toolkit=gtk3 --without-xwidgets
 GENTOO_PACKAGE=app-editors/emacs-25.3 'CFLAGS=-O2 -pipe -march=native
 -g' CPPFLAGS= 'LDFLAGS=-Wl,-O1 -Wl,--as-needed''

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND NOTIFY ACL GNUTLS LIBXML2 ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11

Important settings:
  value of $LANG: en_US.utf8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
"--no-desktop" ignored because the Desktop package is not loaded
Entering debugger...
Back to top level
delete-backward-char: Text is read-only
Making completion list...
You can run the command ‘set-frame-font’ with M-x s-fr-f RET
Mark set
Making completion list...

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message dired format-spec rfc822 mml
mml-sec password-cache epg epg-config gnus-util mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util help-fns mail-prsvr mail-utils
help-mode easymenu cl-loaddefs pcase cl-lib debug time-date mule-util
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel x-win term/common-win x-dnd tool-bar dnd fontset image regexp-opt
fringe tabulated-list newcomment elisp-mode lisp-mode prog-mode register
page menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock
font-lock syntax facemenu font-core frame cl-generic cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european
ethiopic indian cyrillic chinese charscript case-table epa-hook
jka-cmpr-hook help simple abbrev minibuffer cl-preloaded nadvice
loaddefs button faces cus-face macroexp files text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote inotify dynamic-setting move-toolbar
gtk x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 89132 5914)
 (symbols 48 19804 0)
 (miscs 40 56 110)
 (strings 32 16082 4471)
 (string-bytes 1 462916)
 (vectors 16 12028)
 (vector-slots 8 435971 5423)
 (floats 8 162 142)
 (intervals 56 298 4)
 (buffers 976 19))