Added ninth chord (symbol)

[Henry Law]

I've searched the archives and the web generally; all that I have found 
on this subject leads me to believe that the facility I need is not 
there, which is perplexing since it's not particularly esoteric.  Can 
someone either confirm my understanding or put me right?  (I'm using 
2.18.2 on a Debian-based system).

In a lead sheet I want to use the chord which I call an "added ninth". 
Using the key of C as an example, I want the chord C-E-G-D: a plain 
major triad with the ninth added on top.

"add9" is not a valid chord designator in Lilypond, as far as I can see. 
 I can ask for "9" or "maj9" or "sus2" but none of these is my chord:

The ninth is a dominant ninth: C-E-G-Bb-D  Quite a different animal.
Major ninth is C-E-G-B-D
Sus2 is C-D-G, where the third is (temporarily, usually) /replaced/ by 
the second.

Am I stuck?  I'm hoping there is some magic somewhere to help.

--

Henry Law            Manchester, England