Patch #660485: Cygwin _tkinter Tcl/Tk 8.3 patch

The attached patch enables Cygwin Python to
build cleanly against the latest Cygwin Tcl/Tk
which is based on Tcl/Tk 8.3. It also prevents
building against the real X headers, if installed.
diff --git a/Modules/_tkinter.c b/Modules/_tkinter.c
index 0c3d088..212bbad 100644
--- a/Modules/_tkinter.c
+++ b/Modules/_tkinter.c
@@ -57,9 +57,10 @@
 #include <tk.h>
 #endif
 
-/* For Tcl 8.2 and 8.3, CONST* is not defined. */
+/* For Tcl 8.2 and 8.3, CONST* is not defined (except on Cygwin). */
 #ifndef CONST84_RETURN
 #define CONST84_RETURN
+#undef CONST
 #define CONST
 #endif
 
@@ -752,7 +753,7 @@
 	0,			/*tp_hash*/
         0,                      /*tp_call*/
         (reprfunc)PyTclObject_str,        /*tp_str*/
-        PyObject_GenericGetAttr,/*tp_getattro*/
+        0,                      /*tp_getattro*/
         0,                      /*tp_setattro*/
         0,                      /*tp_as_buffer*/
         Py_TPFLAGS_DEFAULT,     /*tp_flags*/
@@ -2838,6 +2839,7 @@
 	PyDict_SetItemString(d, "TkttType", (PyObject *)&Tktt_Type);
 
 	PyTclObject_Type.ob_type = &PyType_Type;
+	PyTclObject_Type.tp_getattro = &PyObject_GenericGetAttr;
 	PyDict_SetItemString(d, "Tcl_Obj", (PyObject *)&PyTclObject_Type);
 
 #ifdef TK_AQUA