[ESS] compilation--ensure-parse error

[Boylan, Ross]

I just updated my ESS code to master and emacs now gives me
Error in post-command-hook: (void-function compilation--ensure-parse)
at the drop of a hat in functions seemingly unrelated to ESS, e.g., when trying to get a directory listing (ctl-X D) it gives the error, then show the usual directory prompt, then shows the error again after I enter a directory and hit enter.  It never shows me the directory listing.

According to the answer for 
http://stackoverflow.com/questions/16122603/font-lock-fontify-keywords-region-symbols-function-definition-is-void-compila
compilation--ensure-parse was introduced in emacs 24.1; I'm running under emacs 23.4.1 (Debian oldstable--was Debian stable until a few weeks ago).

The function is mentioned in lisp/ess-inf.el

Ross