[Freetype] Encodings XLFDs within sfnt

[Juliusz Chroboczek]

In order to preserve bitmap font names as we switch to sfnt for
XFree86, I need to have fonttosfnt put the original font name in some
place where mkfontscale can find it.

The proper way would be to formally define a new sfnt table, for
example ``XF86''.  However, I think it is simpler and quite as
reliable to put a non-standard signature in some standard place.

I'm currently tempted to use the ``comment'' string in the ``name''
table.  I could generate it to be

  XFree86 font, original name was -misc-fixed-...

and then check for this string.

Comments?  Better ideas?

                                        Juliusz