The patch is outdated. Some function prototypes were changed in issue9369, some were changed before.

Here is a new patch. It adds const qualifier to following public functions:
PyObject_DelAttrString, PyObject_HasAttrString, PyObject_GetAttrString, PyObject_SetAttrString, PyObject_DelItemString, PyMapping_DelItemString, PyMapping_HasKeyString, PyMapping_GetItemString, PyMapping_SetItemString, PyFile_FromFd, PyImport_ExecCodeModule, PyImport_ExecCodeModuleEx, PyImport_ExecCodeModuleWithPathnames, PyImport_ImportFrozenModule, PyLong_FromString, PyOS_strtoul, PyOS_strtol, PyOS_Readline, PyMarshal_ReadObjectFromString, PyParser_ParseFile, PyParser_ParseFileFlags, PyParser_ParseFileFlagsEx, PyTokenizer_FromFile. It also changes prototypes of some internal functions and structures and fixes documentation for PyDict_DelItemString. Some of functions already were documented with const qualifier.