title: Crash on call from boost::python::exec( anything )
body: <p>I'm trying to implement some Python stuff into my program and I've decided to use Boost::Python, so I compiled it according to the instructions, with bjam, using mingw/gcc, getting dlls and .a files<br>
  I'm using Code::Blocks for this, so I've put the dlls in the working directory of my project, where the rest of dlls I use are, and decided to run <code>boost::python::exec("b = 5");</code><br>
  Instantly I get a crash. Ideas?<br><br></p>
  
  <pre><code>#include &lt;boost/python.hpp&gt;
  
  float func(int a)
  {
    return a*a-0.5;
  }
  
  BOOST_PYTHON_MODULE(test_module)
  {
    using namespace boost::python;
    def("func", func);
  }
  
  int main()
  {
    //Try one
    boost::python::exec("b = 5");
    //Crash
  
    //Try two
    Py_Initialize();
    boost::python::exec("b = 5");
    //Works fine
  
    //Try three
    Py_Initialize();
    boost::python::exec("import test_module");
    //Throws boost::python::error_already_set and crashes
  
    /*
      Something along the lines of
      boost::python::exec("import test_module\n"
                          "var = test_module.func( 3 )\n");
    */    
  }
  </code></pre>
  
  <p>Under the build options section of my project, I've added <code>libboost_python3-mgw48-d-1_54.dll</code> and <code>libpython33</code> to be linked so it'd compile.<br>
  Ideas?</p>