[Rd] (PR#11054) "Writing R Extensions": bad example with CAR

[anders at ebi.ac.uk]

Prof Brian Ripley wrote:
> I didn't say 'USE_RINTERNALS is not needed' for your code: I said it was 
> not used for the code that was run.

I see. My original point was that the text of the "Writing R extension" 
manual advises against using 'USE_RINTERNALS' but then gives an example 
that only works when this macro is defined, without even pointing out 
this requirement. I merely wanted to suggest adding a little note to the 
manual at this point to make the matter easier for the reader.

Best regards
   Simon Anders