title: Specify cython output file
body: <p>It seems that by default  setup from distutils.core with cmdclass set to build_ext, compiles a cpp or c file in the current working directory.  Is there a way to determine where the generated c code is written to?  Otherwise, a repository will be littered with generated code.</p>
  
  <p>For example this file setup.py will write a file example.c to the current working directory:</p>
  
  <pre><code>from distutils.core import setup
  from Cython.Build import cythonize
  
  setup(
        ext_modules = cythonize("example.pyx"))
  </code></pre>