title: Multiprocessing crash with basic tkinter interface with Python 3.4.3 in OS X
body: <p>I'm trying to run tkinter frames as separate processes, but when I do so using a relatively basic script the process either finishes without starting any windows, or crashes.</p>
  
  <pre><code>from tkinter import *
  from multiprocessing import Process
  
  titles = ['first', 'second', 'third', 'fourth']
  
  class Demo(Frame):
      def __init__(self, parent=None, fname="", **options):
          Frame.__init__(self, master=parent, **options)
          self.pack()
          Label(self, text=fname).pack(side=TOP)
          Button(self, text="Quit!", command=self.quit).pack(side=TOP, fill=BOTH)
  
  def runDemo(name):
      Demo(fname=name).mainloop() #call and run class instance...
  
  if __name__=="__main__":
      for name in titles:
          #runDemo(name)
          Process(target=runDemo, args=(name,)).start() #spawn process...
  </code></pre>
  
  <p>This at least runs if I uncomment the "runDemo(name)" line and comment out the Process call; however, this has the window instances spawn in sequence in the same process, and not in separate processes as desired.</p>
  
  <p>As far as I can tell, everything in this code ought to run the separate processes as expected.</p>
  
  <p>This is using Python 3.4.3 on OS X 10.10.4. I am primarily developing in PyCharm Community Edition 4.5, but this happens when run either in PyCharm or directly from the command line. Any clues?</p>
  
  <p>Updated to add crash logs:</p>
  
  <pre><code>Process:               Python [24917]
  Path:                  /Library/Frameworks/Python.framework/Versions/3.4/Resources/Python.app/Contents/MacOS/Python
  Identifier:            Python
  Version:               3.4.3 (3.4.3)
  Code Type:             X86-64 (Native)
  Parent Process:        Python [24916]
  Responsible:           pycharm [20749]
  User ID:               502
  
  Date/Time:             2015-07-05 17:55:24.271 -0700
  OS Version:            Mac OS X 10.10.4 (14E46)
  Report Version:        11
  Anonymous UUID:        02AA8592-98B0-87D9-7BA0-938C3E157C6B
  
  Sleep/Wake UUID:       DABF4CDD-2502-4E5C-84EB-74CD9BBD6C33
  
  Time Awake Since Boot: 180000 seconds
  Time Since Wake:       8700 seconds
  
  Crashed Thread:        0  Dispatch queue: com.apple.main-thread
  
  Exception Type:        EXC_BAD_ACCESS (SIGSEGV)
  Exception Codes:       KERN_INVALID_ADDRESS at 0x0000000000000110
  
  VM Regions Near 0x110:
  --&gt; 
  __TEXT                 0000000100000000-0000000100001000 [    4K] r-x/rwx SM=COW  /Library/Frameworks/Python.framework/Versions/3.4/Resources/Python.app/Contents/MacOS/Python
  
  Application Specific Information:
  *** multi-threaded process forked ***
  crashed on child side of fork pre-exec
  </code></pre>