bpo-32030: Enhance Py_Main() (#4412)

Parse more env vars in Py_Main():

* Add more options to _PyCoreConfig:

  * faulthandler
  * tracemalloc
  * importtime

* Move code to parse environment variables from _Py_InitializeCore()
  to Py_Main(). This change fixes a regression from Python 3.6:
  PYTHONUNBUFFERED is now read before calling pymain_init_stdio().
* _PyFaulthandler_Init() and _PyTraceMalloc_Init() now take an
  argument to decide if the module has to be enabled at startup.
* tracemalloc_start() is now responsible to check the maximum number
  of frames.

Other changes:

* Cleanup Py_Main():

  * Rename some pymain_xxx() subfunctions
  * Add pymain_run_python() subfunction

* Cleanup Py_NewInterpreter()
* _PyInterpreterState_Enable() now reports failure
* init_hash_secret() now considers pyurandom() failure as an "user
  error": don't fail with abort().
* pymain_optlist_append() and pymain_strdup() now sets err on memory
  allocation failure.

1 files changed, 5 insertions, 3 deletions

diff --git a/Python/pystate.c b/Python/pystate.c
index 30f214e..4544de9 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -76,7 +76,7 @@ _PyRuntimeState_Fini(_PyRuntimeState *runtime)
 
 static void _PyGILState_NoteThreadState(PyThreadState* tstate);
 
-void
+_PyInitError
 _PyInterpreterState_Enable(_PyRuntimeState *runtime)
 {
     runtime->interpreters.next_id = 0;
@@ -85,9 +85,11 @@ _PyInterpreterState_Enable(_PyRuntimeState *runtime)
        initialized here. */
     if (runtime->interpreters.mutex == NULL) {
         runtime->interpreters.mutex = PyThread_allocate_lock();
-        if (runtime->interpreters.mutex == NULL)
-            Py_FatalError("Can't initialize threads for interpreter");
+        if (runtime->interpreters.mutex == NULL) {
+            return _Py_INIT_ERR("Can't initialize threads for interpreter");
+        }
     }
+    return _Py_INIT_OK();
 }
 
 PyInterpreterState *