[3.7] bpo-34247: Fix Python 3.7 initialization (#8659)

* -X dev: it is now possible to override the memory allocator using
  PYTHONMALLOC even if the developer mode is enabled.
* Add _Py_InitializeFromConfig()
* Add _Py_Initialize_ReadEnvVars() to set global configuration
  variables from environment variables
* Fix the code to initialize Python: Py_Initialize() now also reads
  environment variables
* _Py_InitializeCore() can now be called twice: the second call
  only replaces the configuration.
* Write unit tests on Py_Initialize() and the different ways to
  configure Python
* The isolated mode now always sets Py_IgnoreEnvironmentFlag and
  Py_NoUserSiteDirectory to 1.
* pymain_read_conf() now saves/restores the configuration
  if the encoding changed

1 files changed, 10 insertions, 3 deletions

diff --git a/Programs/_freeze_importlib.c b/Programs/_freeze_importlib.c
index b8b630c..7de641e 100644
--- a/Programs/_freeze_importlib.c
+++ b/Programs/_freeze_importlib.c
@@ -74,18 +74,25 @@ main(int argc, char *argv[])
     }
     text[text_size] = '\0';
 
+    _PyCoreConfig config = _PyCoreConfig_INIT;
+    config.program_name = L"./_freeze_importlib";
+    /* Don't install importlib, since it could execute outdated bytecode. */
+    config._disable_importlib = 1;
+
     Py_NoUserSiteDirectory++;
     Py_NoSiteFlag++;
     Py_IgnoreEnvironmentFlag++;
     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-    /* Don't install importlib, since it could execute outdated bytecode.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);
     }
 
+
     if (strstr(inpath, "_external") != NULL) {
         is_bootstrap = 0;
     }