bpo-34170: Add _Py_InitializeFromConfig() (GH-8454)

* If _Py_InitializeCore() is called twice, the second call now copies
  and apply (partially) the new configuration.
* Rename _Py_CommandLineDetails to _PyCmdline
* Move more code into pymain_init(). The core configuration created
  by Py_Main() is new destroyed before running Python to reduce the
  memory footprint.
* _Py_InitializeCore() now returns the created interpreter.
  _Py_InitializeMainInterpreter() now expects an interpreter.
* Remove _Py_InitializeEx_Private(): _freeze_importlib now uses
  _Py_InitializeFromConfig()
* _PyCoreConfig_InitPathConfig() now only computes the path
  configuration if needed.

1 files changed, 12 insertions, 6 deletions

diff --git a/Programs/_freeze_importlib.c b/Programs/_freeze_importlib.c
index b8b630c..03e0826 100644
--- a/Programs/_freeze_importlib.c
+++ b/Programs/_freeze_importlib.c
@@ -74,14 +74,20 @@ main(int argc, char *argv[])
     }
     text[text_size] = '\0';
 
-    Py_NoUserSiteDirectory++;
-    Py_NoSiteFlag++;
-    Py_IgnoreEnvironmentFlag++;
+    _PyCoreConfig config = _PyCoreConfig_INIT;
+    config.user_site_directory = 0;
+    config.site_import = 0;
+    config.ignore_environment = 1;
+    config.program_name = L"./_freeze_importlib";
+    /* Don't install importlib, since it could execute outdated bytecode. */
+    config._install_importlib = 0;
+    config.install_signal_handlers = 1;
+
     Py_FrozenFlag++;
 
-    Py_SetProgramName(L"./_freeze_importlib");
-    /* Don't install importlib, since it could execute outdated bytecode. */
-    _PyInitError err = _Py_InitializeEx_Private(1, 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. */
     if (_Py_INIT_FAILED(err)) {
         _Py_FatalInitError(err);
     }