I'm trying to compile the normalmap plugin http://code.google.com/p/gimp-normalmap/ on Mac, since I can't find a Mac binary for it anywhere. It's failing when looking for the Gimp development libraries. I don't know how to get or install these on a Mac, or, if I already have them somewhere, how to set up pkgconfig or some other part of the build chain to point to the right place. Any tips?