Unable to build python extension with PGXS

Attempting to build a python extension, I'm getting:

Undefined symbols for architecture x86_64:
   "_PyErr_Clear", referenced from:
       _PLyNdarray_FromDatum in pg_ndarray.o
       _PLyObject_To_ndarray in pg_ndarray.o
   "_PyImport_ImportModule", referenced from:
       _PLyNdarray_FromDatum in pg_ndarray.o
       _PLyObject_To_ndarray in pg_ndarray.o
   "_PyObject_CallFunction", referenced from:
       _PLyNdarray_FromDatum in pg_ndarray.o
       _PLyObject_To_ndarray in pg_ndarray.o
   "_PyObject_GetAttrString", referenced from:
       _PLyNdarray_FromDatum in pg_ndarray.o
       _PLyObject_To_ndarray in pg_ndarray.o
   "_PyString_AsString", referenced from:
       _PLyObject_To_ndarray in pg_ndarray.o
   "_PyString_FromStringAndSize", referenced from:
       _PLyNdarray_FromDatum in pg_ndarray.o
   "_PyString_Size", referenced from:
       _PLyObject_To_ndarray in pg_ndarray.o
ld: symbol(s) not found for architecture x86_64

I've included $(python_includespec) in my Makefile:

override CPPFLAGS := $(python_includespec) $(CPPFLAGS)

Is there some other magic I need? Do I need to switch to using
MODULE_big or something?
--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com