title: Produce both versions x32 and x64 under PyInstaller
body: <p>I have installed Python 2.7.xx x64 and trying to build executables with PyInstaller. </p>
  
  <p>Do I have any chance to build both artifacts x32 and x64 with my existing Python x64?</p>
  
  <p>Current PyInstaller script shown below in <strong>app.spec</strong> file:</p>
  
  <blockquote>
    <p>pyinstaller src/app.spec</p>
  </blockquote>
  
  <pre><code># -*- mode: python -*-
  import os
  import platform
  
  from PySide import QtCore
  
  
  onefile = False
  console = False
  
  platform_name = platform.system().lower()
  app_name = {'linux': 'app',
              'darwin': 'app',
              'windows': 'app.exe'}[platform_name]
  
  # Include imageformats plugins
  plugins=os.path.join(os.path.dirname(QtCore.__file__), "plugins\\imageformats")
  static_files = Tree(plugins, 'plugins\\imageformats')
  static_files += [('app.ico', 'src\\app.ico', 'DATA')]
  
  # Analyze sources
  a = Analysis(['src\\app.py'],
               hiddenimports=['pkg_resources'],
               hookspath=None,
               runtime_hooks=None)
  
  pyz = PYZ(a.pure)
  
  if onefile:
      exe = EXE(pyz, a.scripts, a.binaries, a.zipfiles, a.datas, name=app_name,
          debug=False, strip=None, upx=True, console=console, icon='src/app.ico', version='src/app.ver')
  else:
      exe = EXE(pyz, a.scripts, exclude_binaries=True, name=app_name, debug=False,
          strip=None, upx=True, console=console, icon='src/app.ico', version='src/app.ver')
      coll = COLLECT(exe, a.binaries, static_files, a.zipfiles, a.datas, strip=None, upx=True, name='app')
  </code></pre>