title: Scikit-Learn failing to install on OS X: undeclared identifier and assignment errors
body: <p>In trying to install scikit-learn on my machine, I'm running into problems. I'm running OS X 10.8.4 with Python 2.7.5 from Homebrew, and I have the latest versions of Scipy and Numpy installed. </p>
  
  <p>I've tried installing scikit-learn via Pip as well as by cloning the latest source and building from scratch- this is what I get every time it tries to build. Any idea what's going on here?</p>
  
  <pre><code>1 warning and 3 errors generated.
  In file included from sklearn/feature_extraction/_hashing.c:258:
  In file included from /usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/numpy/core/include/numpy/arrayobject.h:15:
  In file included from /usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/numpy/core/include/numpy/ndarrayobject.h:17:
  In file included from /usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/numpy/core/include/numpy/ndarraytypes.h:1728:
  /usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/numpy/core/include/numpy/npy_deprecated_api.h:11:2: warning: "Using deprecated NumPy API, disable it by #defining NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION" [-W#warnings]
  #warning "Using deprecated NumPy API, disable it by #defining NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION"
   ^
  sklearn/feature_extraction/_hashing.c:2439:15: error: assigning to 'int' from incompatible type 'void'
      __pyx_t_2 = PyErr_BadArgument(); if (unlikely(__pyx_t_2 == 0)) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 160; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
                ^ ~~~~~~~~~~~~~~~~~~~
  sklearn/feature_extraction/_hashing.c:4833:96: error: use of undeclared identifier 'PyBoolObject'
    __pyx_ptype_7cpython_4bool_bool = __Pyx_ImportType(__Pyx_BUILTIN_MODULE_NAME, "bool", sizeof(PyBoolObject), 0); if (unlikely(!__pyx_ptype_7cpython_4bool_bool)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 8; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
                                                                                                 ^
  sklearn/feature_extraction/_hashing.c:4834:105: error: use of undeclared identifier 'PyComplexObject'
    __pyx_ptype_7cpython_7complex_complex = __Pyx_ImportType(__Pyx_BUILTIN_MODULE_NAME, "complex", sizeof(PyComplexObject), 0); if (unlikely(!__pyx_ptype_7cpython_7complex_complex)) {__pyx_filename = __pyx_f[5]; __pyx_lineno = 15; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
                                                                                                          ^
  1 warning and 3 errors generated.
  error: Command "cc -fno-strict-aliasing -fno-common -dynamic -I/usr/local/include -I/usr/local/opt/sqlite/include -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk/System/Library/Frameworks/Tk.framework/Versions/8.5/Headers -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/numpy/core/include -I/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/numpy/core/include -I/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c sklearn/feature_extraction/_hashing.c -o build/temp.macosx-10.8-x86_64-2.7/sklearn/feature_extraction/_hashing.o" failed with exit status 1
  </code></pre>