bpo-36763: Add _PyPreConfig._config_init (GH-13481)

* _PyPreConfig_GetGlobalConfig() and  _PyCoreConfig_GetGlobalConfig()
  now do nothing if the configuration was not initialized with
  _PyPreConfig_InitCompatConfig() and _PyCoreConfig_InitCompatConfig()
* Remove utf8_mode=-2 special case: use utf8_mode=-1 instead.
* Fix _PyPreConfig_InitPythonConfig():

  * isolated = 0 instead of -1
  * use_environment = 1 instead of -1

* Rename _PyConfig_INIT to  _PyConfig_INIT_COMPAT
* Rename _PyPreConfig_Init() to _PyPreConfig_InitCompatConfig()
* Rename _PyCoreConfig_Init() to _PyCoreConfig_InitCompatConfig()
* PyInterpreterState_New() now uses _PyCoreConfig_InitPythonConfig()
  as default configuration, but it's very quickly overriden anyway.
* _freeze_importlib.c uses _PyCoreConfig_SetString() to set
  program_name.
* Cleanup preconfig_init_utf8_mode(): cmdline is always non-NULL.

1 files changed, 2 insertions, 2 deletions

diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 6dc684b..21c386b 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -867,7 +867,7 @@ _Py_InitializeCore(_PyRuntimeState *runtime,
     }
 
     _PyCoreConfig local_config;
-    _PyCoreConfig_Init(&local_config);
+    _PyCoreConfig_InitCompatConfig(&local_config);
     err = pyinit_coreconfig(runtime, &local_config, src_config, args, interp_p);
     _PyCoreConfig_Clear(&local_config);
     return err;
@@ -1096,7 +1096,7 @@ Py_InitializeEx(int install_sigs)
     }
 
     _PyCoreConfig config;
-    _PyCoreConfig_Init(&config);
+    _PyCoreConfig_InitCompatConfig(&config);
     config.install_signal_handlers = install_sigs;
 
     err = _Py_InitializeFromConfig(&config);