bpo-36763: Implement the PEP 587 (GH-13592)

* Add a whole new documentation page:
  "Python Initialization Configuration"
* PyWideStringList_Append() return type is now PyStatus,
  instead of int
* PyInterpreterState_New() now calls PyConfig_Clear() if
  PyConfig_InitPythonConfig() fails.
* Rename files:

  * Python/coreconfig.c => Python/initconfig.c
  * Include/cpython/coreconfig.h => Include/cpython/initconfig.h
  * Include/internal/: pycore_coreconfig.h => pycore_initconfig.h

* Rename structures

  * _PyCoreConfig => PyConfig
  * _PyPreConfig => PyPreConfig
  * _PyInitError => PyStatus
  * _PyWstrList => PyWideStringList

* Rename PyConfig fields:

  * use_module_search_paths => module_search_paths_set
  * module_search_path_env => pythonpath_env

* Rename PyStatus field: _func => func
* PyInterpreterState: rename core_config field to config
* Rename macros and functions:

  * _PyCoreConfig_SetArgv() => PyConfig_SetBytesArgv()
  * _PyCoreConfig_SetWideArgv() => PyConfig_SetArgv()
  * _PyCoreConfig_DecodeLocale() => PyConfig_SetBytesString()
  * _PyInitError_Failed() => PyStatus_Exception()
  * _Py_INIT_ERROR_TYPE_xxx enums => _PyStatus_TYPE_xxx
  * _Py_UnixMain() => Py_BytesMain()
  * _Py_ExitInitError() => Py_ExitStatusException()
  * _Py_PreInitializeFromArgs() => Py_PreInitializeFromBytesArgs()
  * _Py_PreInitializeFromWideArgs() => Py_PreInitializeFromArgs()
  * _Py_PreInitialize() => Py_PreInitialize()
  * _Py_RunMain() => Py_RunMain()
  * _Py_InitializeFromConfig() => Py_InitializeFromConfig()
  * _Py_INIT_XXX() => _PyStatus_XXX()
  * _Py_INIT_FAILED() => _PyStatus_EXCEPTION()

* Rename 'err' PyStatus variables to 'status'
* Convert RUN_CODE() macro to config_run_code() static inline function
* Remove functions:

  * _Py_InitializeFromArgs()
  * _Py_InitializeFromWideArgs()
  * _PyInterpreterState_GetCoreConfig()

Objects/exceptions.c

@@ -6,7 +6,7 @@
 
 #define PY_SSIZE_T_CLEAN
 #include <Python.h>
-#include "pycore_coreconfig.h"
+#include "pycore_initconfig.h"
 #include "pycore_object.h"
 #include "pycore_pymem.h"
 #include "pycore_pystate.h"
@@ -2499,13 +2499,13 @@ SimpleExtendsException(PyExc_Warning, ResourceWarning,
 #endif
 #endif /* MS_WINDOWS */
 
-_PyInitError
+PyStatus
 _PyExc_Init(void)
 {
 #define PRE_INIT(TYPE) \
     if (!(_PyExc_ ## TYPE.tp_flags & Py_TPFLAGS_READY)) { \
         if (PyType_Ready(&_PyExc_ ## TYPE) < 0) { \
-            return _Py_INIT_ERR("exceptions bootstrapping error."); \
+            return _PyStatus_ERR("exceptions bootstrapping error."); \
         } \
         Py_INCREF(PyExc_ ## TYPE); \
     }
@@ -2515,7 +2515,7 @@ _PyExc_Init(void)
         PyObject *_code = PyLong_FromLong(CODE); \
         assert(_PyObject_RealIsSubclass(PyExc_ ## TYPE, PyExc_OSError)); \
         if (!_code || PyDict_SetItem(errnomap, _code, PyExc_ ## TYPE)) \
-            return _Py_INIT_ERR("errmap insertion problem."); \
+            return _PyStatus_ERR("errmap insertion problem."); \
         Py_DECREF(_code); \
     } while (0)
 
@@ -2589,14 +2589,14 @@ _PyExc_Init(void)
     PRE_INIT(TimeoutError);
 
     if (preallocate_memerrors() < 0) {
-        return _Py_INIT_ERR("Could not preallocate MemoryError object");
+        return _PyStatus_ERR("Could not preallocate MemoryError object");
     }
 
     /* Add exceptions to errnomap */
     if (!errnomap) {
         errnomap = PyDict_New();
         if (!errnomap) {
-            return _Py_INIT_ERR("Cannot allocate map from errnos to OSError subclasses");
+            return _PyStatus_ERR("Cannot allocate map from errnos to OSError subclasses");
         }
     }
 
@@ -2622,7 +2622,7 @@ _PyExc_Init(void)
     ADD_ERRNO(ProcessLookupError, ESRCH);
     ADD_ERRNO(TimeoutError, ETIMEDOUT);
 
-    return _Py_INIT_OK();
+    return _PyStatus_OK();
 
 #undef PRE_INIT
 #undef ADD_ERRNO
@@ -2630,12 +2630,12 @@ _PyExc_Init(void)
 
 
 /* Add exception types to the builtins module */
-_PyInitError
+PyStatus
 _PyBuiltins_AddExceptions(PyObject *bltinmod)
 {
 #define POST_INIT(TYPE) \
     if (PyDict_SetItemString(bdict, # TYPE, PyExc_ ## TYPE)) { \
-        return _Py_INIT_ERR("Module dictionary insertion problem."); \
+        return _PyStatus_ERR("Module dictionary insertion problem."); \
     }
 
 #define INIT_ALIAS(NAME, TYPE) \
@@ -2644,7 +2644,7 @@ _PyBuiltins_AddExceptions(PyObject *bltinmod)
         Py_XDECREF(PyExc_ ## NAME); \
         PyExc_ ## NAME = PyExc_ ## TYPE; \
         if (PyDict_SetItemString(bdict, # NAME, PyExc_ ## NAME)) { \
-            return _Py_INIT_ERR("Module dictionary insertion problem."); \
+            return _PyStatus_ERR("Module dictionary insertion problem."); \
         } \
     } while (0)
 
@@ -2652,7 +2652,7 @@ _PyBuiltins_AddExceptions(PyObject *bltinmod)
 
     bdict = PyModule_GetDict(bltinmod);
     if (bdict == NULL) {
-        return _Py_INIT_ERR("exceptions bootstrapping error.");
+        return _PyStatus_ERR("exceptions bootstrapping error.");
     }
 
     POST_INIT(BaseException);
@@ -2729,7 +2729,7 @@ _PyBuiltins_AddExceptions(PyObject *bltinmod)
     POST_INIT(ProcessLookupError);
     POST_INIT(TimeoutError);
 
-    return _Py_INIT_OK();
+    return _PyStatus_OK();
 
 #undef POST_INIT
 #undef INIT_ALIAS