Log Message:
emacs27: switch to harfbuzz backend for fonts

This is the dependency recommended by upstream.

While here, clean up options:
- remove undocumented duplicate name for the same option (lucid)
- remove xaw3d from default options since it has no effect with gtk,
  which is on by default
- remove gconf option, since gsettings (via glib) is preferred,
  and gconfmm dependency was wrong anyway

Bump PKGREVISION.