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, 2 insertions, 2 deletions

diff --git a/Python/bootstrap_hash.c b/Python/bootstrap_hash.c
index e667fa93f0..610541d810 100644
--- a/Python/bootstrap_hash.c
+++ b/Python/bootstrap_hash.c
@@ -594,8 +594,8 @@ init_hash_secret(int use_hash_seed,
            pyurandom() is non-blocking mode (blocking=0): see the PEP 524. */
         res = pyurandom(secret, secret_size, 0, 0);
         if (res < 0) {
-            return _Py_INIT_ERR("failed to get random numbers "
-                                "to initialize Python");
+            return _Py_INIT_USER_ERR("failed to get random numbers "
+                                     "to initialize Python");
         }
     }
     return _Py_INIT_OK();