The newest gcc emmits this warning:
```
/Modules/_tkinter.c:272:9: warning: this ‘if’ clause does not guard... [-Wmisleading-indentation]
272 | if(tcl_lock)PyThread_acquire_lock(tcl_lock, 1); tcl_tstate = tstate; }
| ^~
/Modules/_tkinter.c:2869:5: note: in expansion of macro ‘LEAVE_PYTHON’
2869 | LEAVE_PYTHON
| ^~~~~~~~~~~~
/Modules/_tkinter.c:243:5: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the ‘if’
243 | (*(PyThreadState**)Tcl_GetThreadData(&state_key, sizeof(PyThreadState*)))
| ^
/Modules/_tkinter.c:272:57: note: in expansion of macro ‘tcl_tstate’
272 | if(tcl_lock)PyThread_acquire_lock(tcl_lock, 1); tcl_tstate = tstate; }
| ^~~~~~~~~~
/Modules/_tkinter.c:2869:5: note: in expansion of macro ‘LEAVE_PYTHON’
2869 | LEAVE_PYTHON
```
that's because the macro packs together two statements at the same level
as the "if". The warning is misleading but is very noisy so it makes
sense to fix it.
Add a new Py_TPFLAGS_DISALLOW_INSTANTIATION type flag to disallow
creating type instances: set tp_new to NULL and don't create the
"__new__" key in the type dictionary.
The flag is set automatically on static types if tp_base is NULL or
&PyBaseObject_Type and tp_new is NULL.
Use the flag on the following types:
* _curses.ncurses_version type
* _curses_panel.panel
* _tkinter.Tcl_Obj
* _tkinter.tkapp
* _tkinter.tktimertoken
* _xxsubinterpretersmodule.ChannelID
* sys.flags type
* sys.getwindowsversion() type
* sys.version_info type
Update MyStr example in the C API documentation to use
Py_TPFLAGS_DISALLOW_INSTANTIATION.
Add _PyStructSequence_InitType() function to create a structseq type
with the Py_TPFLAGS_DISALLOW_INSTANTIATION flag set.
type_new() calls _PyType_CheckConsistency() at exit.
No longer use deprecated aliases to functions:
* Replace PyObject_MALLOC() with PyObject_Malloc()
* Replace PyObject_REALLOC() with PyObject_Realloc()
* Replace PyObject_FREE() with PyObject_Free()
* Replace PyObject_Del() with PyObject_Free()
* Replace PyObject_DEL() with PyObject_Free()
No longer use deprecated aliases to functions:
* Replace PyMem_MALLOC() with PyMem_Malloc()
* Replace PyMem_REALLOC() with PyMem_Realloc()
* Replace PyMem_FREE() with PyMem_Free()
* Replace PyMem_Del() with PyMem_Free()
* Replace PyMem_DEL() with PyMem_Free()
Modify also the PyMem_DEL() macro to use directly PyMem_Free().
Change spelling of a #define in _tkinter.c from HAVE_LIBTOMMAMTH to HAVE_LIBTOMMATH, since this is used to keep track of tclTomMath.h, not tclTomMamth.h. No other file seems to refer to this variable.
The PyFPE_START_PROTECT() and PyFPE_END_PROTECT() macros are empty:
they have been doing nothing for the last year (since commit
735ae8d139), so stop using them.
On Windows use UTF-16 (or UTF-32 for 32-bit Tcl_UniChar) with the
"surrogatepass" error handler for converting to/from Tcl Unicode objects.
On Linux use UTF-8 with the "surrogateescape" error handler for converting
to/from Tcl String objects.
Converting strings from Tcl to Python and back now never fails
(except MemoryError).
In ArgumentClinic, value "NULL" should now be used only for unrepresentable default values
(like in the optional third parameter of getattr). "None" should be used if None is accepted
as argument and passing None has the same effect as not passing the argument at all.
Add a new public PyObject_CallNoArgs() function to the C API: call a
callable Python object without any arguments.
It is the most efficient way to call a callback without any argument.
On x86-64, for example, PyObject_CallFunctionObjArgs(func, NULL)
allocates 960 bytes on the stack per call, whereas
PyObject_CallNoArgs(func) only allocates 624 bytes per call.
It is excluded from stable ABI 3.8.
Replace private _PyObject_CallNoArg() with public
PyObject_CallNoArgs() in C extensions: _asyncio, _datetime,
_elementtree, _pickle, _tkinter and readline.
There was few cases of using literal 0 instead of NULL in the context of
pointers. While this was a legitimate C code, using NULL rather than 0 makes
the code clearer.
