gh-105145: Remove old functions to config Python init (#105154)

Remove the following old functions to configure the Python
initialization, deprecated in Python 3.11:

* PySys_AddWarnOptionUnicode()
* PySys_AddWarnOption()
* PySys_AddXOption()
* PySys_HasWarnOptions()
* PySys_SetArgvEx()
* PySys_SetArgv()
* PySys_SetPath()
* Py_SetPath()
* Py_SetProgramName()
* Py_SetPythonHome()
* Py_SetStandardStreamEncoding()
* _Py_SetProgramFullPath()

Most of these functions are kept in the stable ABI, except:

* Py_SetStandardStreamEncoding()
* _Py_SetProgramFullPath()

Update Doc/extending/embedding.rst and Doc/extending/extending.rst to
use the new PyConfig API.

_testembed.c:

* check_stdio_details() now sets stdio_encoding and stdio_errors
  of PyConfig.
* Add definitions of functions removed from the API but kept in the
  stable ABI.
* test_init_from_config() and test_init_read_set() now use
  PyConfig_SetString() instead of PyConfig_SetBytesString().

Remove _Py_ClearStandardStreamEncoding() internal function.

1 files changed, 20 insertions, 0 deletions

diff --git a/Doc/whatsnew/3.13.rst b/Doc/whatsnew/3.13.rst
index e263d0b..cdc48a5 100644
--- a/Doc/whatsnew/3.13.rst
+++ b/Doc/whatsnew/3.13.rst
@@ -375,3 +375,23 @@ Removed
   * ``PyEval_CallMethod()``: use :c:func:`PyObject_CallMethod` instead.
 
   (Contributed by Victor Stinner in :gh:`105107`.)
+
+* Remove the following old functions to configure the Python initialization,
+  deprecated in Python 3.11:
+
+  * ``PySys_AddWarnOptionUnicode()``: use :c:member:`PyConfig.warnoptions` instead.
+  * ``PySys_AddWarnOption()``: use :c:member:`PyConfig.warnoptions` instead.
+  * ``PySys_AddXOption()``: use :c:member:`PyConfig.xoptions` instead.
+  * ``PySys_HasWarnOptions()``: use :c:member:`PyConfig.xoptions` instead.
+  * ``PySys_SetArgvEx()``: set :c:member:`PyConfig.argv` instead.
+  * ``PySys_SetArgv()``: set :c:member:`PyConfig.argv` instead.
+  * ``PySys_SetPath()``: set :c:member:`PyConfig.module_search_paths` instead.
+  * ``Py_SetPath()``: set :c:member:`PyConfig.module_search_paths` instead.
+  * ``Py_SetProgramName()``: set :c:member:`PyConfig.program_name` instead.
+  * ``Py_SetPythonHome()``: set :c:member:`PyConfig.home` instead.
+  * ``Py_SetStandardStreamEncoding()``: set :c:member:`PyConfig.stdio_encoding` instead.
+  * ``_Py_SetProgramFullPath()``: set :c:member:`PyConfig.executable` instead.
+
+  Use the new :c:type:`PyConfig` API of the :ref:`Python Initialization
+  Configuration <init-config>` instead (:pep:`587`), added to Python 3.8.
+  (Contributed by Victor Stinner in :gh:`105145`.)