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, 17 insertions, 5 deletions

diff --git a/Programs/_freeze_importlib.c b/Programs/_freeze_importlib.c
index 1a719e2..8cf44d3 100644
--- a/Programs/_freeze_importlib.c
+++ b/Programs/_freeze_importlib.c
@@ -76,18 +76,30 @@ main(int argc, char *argv[])
     }
     text[text_size] = '\0';
 
+    _PyInitError err;
     _PyCoreConfig config;
-    _PyCoreConfig_InitIsolatedConfig(&config);
+
+    err = _PyCoreConfig_InitIsolatedConfig(&config);
+    if (_PyInitError_Failed(err)) {
+        _PyCoreConfig_Clear(&config);
+        _Py_ExitInitError(err);
+    }
 
     config.site_import = 0;
-    config.program_name = L"./_freeze_importlib";
+
+    err = _PyCoreConfig_SetString(&config, &config.program_name,
+                                  L"./_freeze_importlib");
+    if (_PyInitError_Failed(err)) {
+        _PyCoreConfig_Clear(&config);
+        _Py_ExitInitError(err);
+    }
+
     /* Don't install importlib, since it could execute outdated bytecode. */
     config._install_importlib = 0;
     config._init_main = 0;
 
-    _PyInitError err = _Py_InitializeFromConfig(&config);
-    /* No need to call _PyCoreConfig_Clear() since we didn't allocate any
-       memory: program_name is a constant string. */
+    err = _Py_InitializeFromConfig(&config);
+    _PyCoreConfig_Clear(&config);
     if (_PyInitError_Failed(err)) {
         _Py_ExitInitError(err);
     }