build failure on OSX

[Carlo De Falco]

Hi,

I just pulled from the repo default branch and tried to build revision 
90689bdbe048.
The buold fails wit the error :

../octave/libinterp/version.cc:92:20: error: no member named 'config' in 
namespace 'octave'
         + octave::config::canonical_host_type ()
           ~~~~~~~~^

It seems this is due to the fact that libinterp/version.cc has 

  #include "defaults.h"

but defaults.h is in the subdirectory libinterp/corefcn, using 

 #include "corefcn/defaults.h"

fixes this problem for me, but then I get similar issues in other files, for 
example:

../octave/libinterp/octave-value/ov-dld-fcn.cc:51:38: error: no member named 
'config' in namespace 'octave'
  std::string oct_file_dir = octave::config::oct_file_dir ();

was defaults.h recently moved? what is a clean way to deal with this? Is anyone 
else seing the same problem? should I file a bug?

thanks,
c.