Define _Py_ABI_SLOT using _PyABIInfo_DEFAULT

_PyABIInfo_DEFAULT is available in Include/modsupport.h, there's not need
to duplicate the definition here.

Rename from _Py_INTERNAL_ABI_SLOT, as it's no longer internal.

Author: befeleme

Include/cpython/modsupport.h

@@ -38,14 +38,8 @@ typedef struct _PyArg_Parser {
 PyAPI_FUNC(int) _PyArg_ParseTupleAndKeywordsFast(PyObject *, PyObject *,
                                                  struct _PyArg_Parser *, ...);
 
-#ifdef Py_BUILD_CORE
-// Internal; defined here to avoid explicitly including pycore_modsupport.h
-#define _Py_INTERNAL_ABI_SLOT                             \
-    {Py_mod_abi, (void*) &(PyABIInfo) {                   \
-        .abiinfo_major_version = 1,                       \
-        .abiinfo_minor_version = 0,                       \
-        .flags = PyABIInfo_INTERNAL,                      \
-        .build_version = PY_VERSION_HEX,                  \
-        .abi_version = PY_VERSION_HEX }}                  \
+// For internal use in stdlib. Needs C99 compound literals.
+// Defined here to avoid every stdlib module including pycore_modsupport.h
+#define _Py_ABI_SLOT                                      \
+    {Py_mod_abi, (void*) &(PyABIInfo) _PyABIInfo_DEFAULT} \
     ///////////////////////////////////////////////////////
-#endif

Modules/_datetimemodule.c

@@ -7656,7 +7656,7 @@ _datetime_exec(PyObject *module)
 }
 
 static PyModuleDef_Slot module_slots[] = {
-    _Py_INTERNAL_ABI_SLOT,
+    _Py_ABI_SLOT,
     {Py_mod_exec, _datetime_exec},
     {Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
     {Py_mod_gil, Py_MOD_GIL_NOT_USED},