[poppler] Fixing bug 36111

[Max Filippov]

Hi.

There's bugzilla entry 36111 "(forms_unicode) text in Russian in pdf forms", https://bugs.freedesktop.org/show_bug.cgi?id=36111
Looks like nobody's working on it. I'm also hit by this bug and I'd like to fix it.

I see the issue is the following:
- unicode-to-charcode map is not loaded from an external font, even when
there's cmap table in it;
- form text conversion by the ccToUnicode->mapToCharCode fails for the symbols
with codes > 255 in AnnotWidget::layoutText;

Do I understand it right that provision of GfxFont subclass that can load an
appropriate cmap table and initialize its CharCodeToUnicode instance with it is
the right way to deal with this bug, or is there a better way?

And BTW, what is the relation between this mailing list and the bugzilla?

Thanks.
-- Max