texinfo source of elisp reference manual: missing index

[Le TeXnicien de Surface]

Hello all,

I've just downloaded the texinfo sources of the 'Emacs lisp reference
manual' to produce a a4paper version for selected printing but the
index.texi is a link to a index.unperm and, when compiling with texi2pdf,  
I keep obtaining a warning about missing index file and even after
texindex-ing I can't obtain a complete version.

What am I missing?
-- 
Le TeXnicien de Surface