pdf doesn't make ps first

[Graham Percival]

foo.ly:  { c4 }

Lilypond fails to create pdf, but if I create a ps first, (lilypond 
--ps foo.ly), it works.  Should lilypond --pdf call lilypond --ps (or 
--dvi) first?

OSX, recent CVS.


------- output
spark:~/tmp gperciva$ lilypond --pdf foo.ly

Now processing `foo.ly'
Parsing...
Interpreting music... [1]
Preprocessing graphical objects...
Calculating line breaks... [2]
Paper output to `foo.tex'...Invoking "dvips -t a4   -u+ec-mftrace.map 
-u+lilypond.map -Ppdf foo"
This is dvips(k) 5.92b Copyright 2002 Radical Eye Software 
(www.radicaleye.com)
dvips: ! DVI file can't be opened.

Converting to `foo.pdf'...
Error: /undefinedfilename in (foo.ps)
Operand stack:

Execution stack:
   %interp_exit   .runexec2   --nostringval--   --nostringval--   
--nostringval--   2   %stopped_push   --nostringval--   --nostringval-- 
  --nostringval--   false   1   %stopped_push   --nostringval--   
--nostringval--
Dictionary stack:
   --dict:1049/1123(ro)(G)--   --dict:0/20(G)--   --dict:69/200(L)--
Current allocation mode is local
Last OS error: 2
AFPL Ghostscript 8.00: Unrecoverable error, exit code 1

spark:~/tmp gperciva$