title: py2app SyntaxError when running with python3.3
body: <p>I have written a sudoku solver using especially, but not only, tkinter and multiprocessing. I want to make it a standalone app, which I'm using py2app for.</p>
  
  <p>I've run py2applet-3.3 --make-setup sudoku_app.py (that is what it's called when installed through macports), and it succeeded at that. However when building with python3.3 (python3.3 setup.py py2app), it returns a SyntaxError with an almost endless stack trace that ends like this:</p>
  
  <pre><code>File "/opt/local/Library/Frameworks/Python.framework/Versions/3.3/lib/python3.3/site-packages/modulegraph/modulegraph.py", line 954, in load_module
  co = compile(contents, pathname, 'exec', 0, True)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.3/lib/python3.3/site-packages/sympy/mpmath/libmp/exec_py2.py", line 2
  exec string in globals, locals
            ^
  SyntaxError: invalid syntax
  </code></pre>
  
  <p>When running the same setup file with python2.7, it does succeed to build, but there's a bunch of errors when trying to run the created .app. I've written my code in python3, although trying to maintain python2 compatibility through various try ... except - blocks and from <strong>future</strong> imports. At some point though, it got too complicated and I decided to just go with python3.</p>
  
  <p>Why does py2app not work with python3 there?</p>