gh-111178: Avoid calling functions from incompatible pointer types in _tkinter.c

[chrstphrchvz]

Potential compiler warnings eliminated:

./Modules/_tkinter.c:819:18: warning: cast from 'PyObject *(*)(PyTclObject *, void *)' (aka 'struct _object *(*)(PyTclObject *, void *)') to 'getter' (aka 'struct _object *(*)(struct _object *, void *)') converts to incompatible function type [-Wcast-function-type-strict]
  819 |     {"typename", (getter)get_typename, NULL, get_typename__doc__},
      |                  ^~~~~~~~~~~~~~~~~~~~
./Modules/_tkinter.c:820:16: warning: cast from 'PyObject *(*)(PyTclObject *, void *)' (aka 'struct _object *(*)(PyTclObject *, void *)') to 'getter' (aka 'struct _object *(*)(struct _object *, void *)') converts to incompatible function type [-Wcast-function-type-strict]
  820 |     {"string", (getter)PyTclObject_string, NULL,
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~
./Modules/_tkinter.c:826:21: warning: cast from 'void (*)(PyTclObject *)' to 'destructor' (aka 'void (*)(struct _object *)') converts to incompatible function type [-Wcast-function-type-strict]
  826 |     {Py_tp_dealloc, (destructor)PyTclObject_dealloc},
      |                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./Modules/_tkinter.c:827:18: warning: cast from 'PyObject *(*)(PyTclObject *)' (aka 'struct _object *(*)(PyTclObject *)') to 'reprfunc' (aka 'struct _object *(*)(struct _object *)') converts to incompatible function type [-Wcast-function-type-strict]
  827 |     {Py_tp_repr, (reprfunc)PyTclObject_repr},
      |                  ^~~~~~~~~~~~~~~~~~~~~~~~~~
./Modules/_tkinter.c:828:17: warning: cast from 'PyObject *(*)(PyTclObject *)' (aka 'struct _object *(*)(PyTclObject *)') to 'reprfunc' (aka 'struct _object *(*)(struct _object *)') converts to incompatible function type [-Wcast-function-type-strict]
  828 |     {Py_tp_str, (reprfunc)PyTclObject_str},
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~
./Modules/_tkinter.c:1388:23: warning: cast from 'int (*)(Tkapp_CallEvent *, int)' (aka 'int (*)(struct Tkapp_CallEvent *, int)') to 'Tcl_EventProc *' (aka 'int (*)(struct Tcl_Event *, int)') converts to incompatible function type [-Wcast-function-type-strict]
 1388 |         ev->ev.proc = (Tcl_EventProc*)Tkapp_CallProc;
      |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./Modules/_tkinter.c:1666:23: warning: cast from 'int (*)(VarEvent *, int)' (aka 'int (*)(struct VarEvent *, int)') to 'Tcl_EventProc *' (aka 'int (*)(struct Tcl_Event *, int)') converts to incompatible function type [-Wcast-function-type-strict]
 1666 |         ev->ev.proc = (Tcl_EventProc*)var_proc;
      |                       ^~~~~~~~~~~~~~~~~~~~~~~~
./Modules/_tkinter.c:2293:23: warning: cast from 'int (*)(CommandEvent *, int)' (aka 'int (*)(struct CommandEvent *, int)') to 'Tcl_EventProc *' (aka 'int (*)(struct Tcl_Event *, int)') converts to incompatible function type [-Wcast-function-type-strict]
 2293 |         ev->ev.proc = (Tcl_EventProc*)Tkapp_CommandProc;
      |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./Modules/_tkinter.c:2346:23: warning: cast from 'int (*)(CommandEvent *, int)' (aka 'int (*)(struct CommandEvent *, int)') to 'Tcl_EventProc *' (aka 'int (*)(struct Tcl_Event *, int)') converts to incompatible function type [-Wcast-function-type-strict]
 2346 |         ev->ev.proc = (Tcl_EventProc*)Tkapp_CommandProc;
      |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Issue: UBSan: Calling a function through pointer to incorrect function type is undefined behavior #111178