Catch exception when signal is used in the non-main thread

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_4_BRANCH@23835 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

wxPython/src/_extras.py

@@ -976,8 +976,11 @@ of your Mac."""
         # KeyboardInterrupt???)  but will later segfault on exit.  By
         # setting the default handler then the app will exit, as
         # expected (depending on platform.)
-        import signal
-        signal.signal(signal.SIGINT, signal.SIG_DFL)
+        try:
+            import signal
+            signal.signal(signal.SIGINT, signal.SIG_DFL)
+        except:
+            pass
 
         # this initializes wxWindows and then calls our OnInit
         _wxStart(self.OnInit)