Ok, so let me make a rather adventurous proposal. I will assume you have the TeXLive 2012 distribution, as this is the only one I am familiar with.
- install
libertine-legacy in the local texmf tree
- find the file
libertine.sty in texmf-local/tex/latex/libertine-legacy/
and rename it to libertine-legacy.sty (we are not going to use it as it may
certainly create havoc with the newer libertine.sty which is in 2012/texmf-dist)
- find the file
libertine.map in texmf-local/fonts/map/dvips/libertine-legacy/
and rename it to libertine-legacy.map
- go to
texmf-local/web2c and add the line Map libertine-legacy.map to the file updmap.cfg (you may have to create that file)
- run
texhash on the repertory texmf-local
- run
updmap-sys or updmap depending on your previous habits (I personally only and exclusively use updmap-sys)
You are now ready to access the Greek glyphs from the legacy libertine type-1 fonts in the following manner:
\documentclass{article}
%% the next two lines are for the *new* libertine
\usepackage[T1]{fontenc}
\usepackage{libertine}
%% these next lines are for the *legacy* libertine, especially the Greek glyphs
\begingroup
\makeatletter
\newcommand*\DeclareTextGlyphX[5]{%
% \DeclareTextGlyphX{fxl}{U}{fxla7}{uniA7F1}{241}
% #1=basefont #2=encoding #3=fontfamily #4=glyphname, #5=position
\global\@namedef{legacy#1#4}{{\fontfamily{#3}\fontencoding{#2}\selectfont\char#5\relax}}}
\input{fxl.inc}
\endgroup
\begin{document}
\legacyfxldelta
\legacyfxlDelta
\end{document}
The files of my version of the legacy package are dated from December 2011. I hope this is the latest version, and that there has not been in the meantime changes in the font names in the legacy thing.
Let me insist that what I describe here does not replace the new libertine with the libertine-legacy. Both need to be installed: the new one in your main tree, the legacy one in the local tree. And you need to change the names of the legacy .sty and .map files as indicated, and then don't forget to do texhash and updmap-sys.

pdflatexmake available the glyphs that previously one could get with\libertineGlyph. It's not just a definition problem. – egreg Dec 10 '12 at 00:01pdfLatex) by installing the old package? – Mohan Dec 10 '12 at 00:08\documentclass{standalone}\usepackage{libertine}\begin{document}\char934\end{document}, and\includegraphicsthe resulting PDF with pdfLaTeX. – Qrrbrbirlbel Dec 10 '12 at 00:55libertine-legacyin a local texmf tree. – Speravir Dec 10 '12 at 04:08