title: distutilscross issue when install PyAudio for cross-platform
body: <p>When I installed PyAuduo for my MIPS embedded platform, I got this error:</p>
  
  <pre><code> running build
   Traceback (most recent call last):
   File "setup.py", line 122, in &lt;module&gt;
   extra_link_args=extra_link_args)
   File "/usr/local/lib/python3.5/distutils/core.py", line 148, in setup
       dist.run_commands()
   File "/usr/local/lib/python3.5/distutils/dist.py", line 955, in 
     run_commands
     self.run_command(cmd)
    File "/usr/local/lib/python3.5/distutils/dist.py", line 973, in 
   run_command
     cmd_obj.ensure_finalized()
    File "/usr/local/lib/python3.5/distutils/cmd.py", line 107, in  
       ensure_finalized
     self.finalize_options()
     File "/usr/local/lib/python3.5/site-packages/distutilscross-0.1-   
      py3.5.egg/distutilscross/crosscompile.py", line 16, in finalize_options
     AttributeError: '_Environ' object has no attribute 'has_key'
  </code></pre>
  
  <p>It seems "crosscompile.py" cannot run python3 normally. 
  Does anyone have idea how to modify the code in crosscompile.py to work normally in pyhton3?</p>