Purpose: Document (particularly core distribution) Tcl and Tk differences
between supported platforms.

   * Features unique to X Windows versions of Tk
   1. -display support

   * Features unique to Microsoft Windows versions of Tk
   1. [[What are the Windows specific extensions - like registry, etc.]]

   * Features unique to Apple MacOS X versions of Tk
   1. [[What are the MacOS X specific extensions]]

   * Features which work differently 
   1. Native widgets on Windows/MacOS X vs Unix Tcl and C widgets [[is there a wiki page detailing which of these exist]]
   2. menu unpost is documented to not work on windows
   3. [[wm attributes]] takes different values on Windows/MacOS, and does nothing on Unix (in Tcl/Tk 8.4.9.0, at least).


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[Category Porting]