[Fontconfig] Missing glyph display in various font formats

[James Cloos]

I'm not sure whether this is an app-specific issue or a library issue,
so I'll start here and move if it should be an app issue....

One anoyance I have with Xft as compared to server-side fonts is most
easily seen in xfd(1x):  with -fn empty glyphs result in empty boxes
in the grid; with -fa and a sfnt font you get those anoying box glyphs.

The extra noise makes it difficult to tell at a glance what glyphs
exist on the current page.  

Should fontconfig have a way of overriding the missing glyphs?
Perhaps something akin to <blank/>, but specifying a glyph id
rather than a character code?

Or should freetype?

Or is this too app-specific, and should it be a xfd(1x) bug report?

-JimC
-- 
James H. Cloos, Jr. <cloos at jhcloos.com>