title: Cython: Symbol not found: _PyCFunction_Check
body: <p>I am trying to get the <a href="http://docs.cython.org/src/userguide/tutorial.html" rel="nofollow">basic Cython tutorial</a> to work. So I have</p>
  
  <p><code>hello.pyx</code>:</p>
  
  <pre><code>def say_hello_to(name):
      print("Hello %s!" % name)
  </code></pre>
  
  <p>And <code>setup.py</code>:</p>
  
  <pre><code>from distutils.core import setup
  from distutils.extension import Extension
  from Cython.Distutils import build_ext
  
  ext_modules = [Extension("hello", ["hello.pyx"])]
  
  setup(
    name = 'Hello world app',
    cmdclass = {'build_ext': build_ext},
    ext_modules = ext_modules
  )
  </code></pre>
  
  <p>However, trying to compile I get this error:</p>
  
  <pre><code>$ python setup.py build_ext --inplace
  running build_ext
  failed to import Cython: dlopen(/usr/local/lib/python2.7/site-packages/Cython/Compiler/Scanning.so, 2): Symbol not found: _PyCFunction_Check
    Referenced from: /usr/local/lib/python2.7/site-packages/Cython/Compiler/Scanning.so
    Expected in: flat namespace
   in /usr/local/lib/python2.7/site-packages/Cython/Compiler/Scanning.so
  error: Cython does not appear to be installed
  </code></pre>
  
  <p>Cython <em>is</em> installed and <code>scanning.so</code> does appear to contain the symbol in question:</p>
  
  <pre><code>$ nm -gl /usr/local/lib/python2.7/site-packages/Cython/Compiler/Scanning.so | grep _PyCFunction_Check
               U _PyCFunction_Check
  </code></pre>
  
  <p>Any ideas? I'm on OS X 10.7.5 using homebrew python 2.7.3.</p>
  
  <p><strong>Edit:</strong> As pointed out by @bdash' comment below, <code>U _PyCFunction_Check</code> actually means that  <code>_PyCFunction_Check</code> is undefined.</p>