[O] latex listings number-lines problems with new exporter

[Thomas Alexander Gerds]

Hi 

using org-mode "7.9.3f" and the new exporter I was desperately trying to
get line numbers back for exported R code blocks using the latex listing
package. first I tried

(setq org-latex-listings-options
    '(("basicstyle" "\\small")
      ("numbers" "left")))

which gives

,----
| \lstset{basicstyle=\small,numbers=left,language=R,numbers=none}      
`----

that this is possible seems sub-optimal :)

some debugging led me via org-latex-src-block to
org-element-src-block-parser which indicated adding a switch "-n" behind
to the scr-block:

,----
| #+BEGIN_SRC R -n :results output raw  :exports both  :session *R* :cache yes


this works and has a new feature (switch +n) which allows numbering to
be continued in subsequent blocks.

Now, I would like to set numbers on globally or buffer-local for all
blocks. But is it possible to set a switch globally?  I think parameters
can still be set with an appropriate #+PROPERTY: statement!?

whatever the answer, it would be nice if this feature was mentioned in
the help string of org-latex-listing-options.

regards,
Thomas