[XeTeX] how to do (better) searchable PDFs in xelatex?

[Joe Corneli]

On Mon, Oct 15, 2012 at 9:13 AM, Mojca Miklavec
<mojca.miklavec.lists at gmail.com> wrote:

> I might be wrong, but pdfTeX-generated documents work fine (after
> adding encoding vector) even though the glyphs populate "random" slots
> is the font (for example T1 encoding) that have nothing to do with
> Unicode.
>
> It should be possible to do something similar in XeTeX/LuaTeX.
>
> I'm not saying that this would solve problems of copy-pasting Arabic
> scripts, but it should be possible to cover alternate glyphs for Latin
> scripts at least.

Sounds like a possible solution to my problem...  and indeed, this MWE
is searchable --

\documentclass{book}
\usepackage{libertine}
\begin{document}
Quantitative/Prefix.
\end{document}

... without the Qu =>  ligature, but fi => fi, despite the latter
copy-pasting as "fi".  Somehow this does seem like it's just an
oversight on the part of the font developers.  Indeed, it seems this
is already noted in their bug tracker:

http://sourceforge.net/tracker/index.php?func=detail&aid=3575137&group_id=89513&atid=590374

I guess there's little else to do but wait until that's fixed.