Allow GIL to be disabled in whirlpool C extension

In 3.13 python extensions need to declare support for GIL features, for
example if they don't declare Py_MOD_GIL_NOT_USED then it will cause the
GIL to be enabled even when python was launched in free-threaded mode.

This requires "multi-phase initialization" because Py_mod_create is
incompatible with m_slots. There's a PyUnstable_Module_SetGIL() function
that can be used with single-phase init, but it's an unstable API, so
it's better to use multi-phase init. There's no need to use
PyModule_GetState() because the whirlpool module has no mutable state.

Bug: https://bugs.gentoo.org/934220
Signed-off-by: Zac Medico <[email protected]>

src/portage_util__whirlpool.c

@@ -1112,30 +1112,42 @@ static PyTypeObject WhirlpoolType = {
  .tp_methods = Whirlpool_methods,
 };
 
+static int
+whirlpool_exec(PyObject *mod)
+{
+ if (PyType_Ready(&WhirlpoolType) < 0)
+ return -1;
+
+ Py_INCREF(&WhirlpoolType);
+ if (PyModule_AddObject(mod, "Whirlpool", (PyObject *) &WhirlpoolType) < 0) {
+ Py_DECREF(&WhirlpoolType);
+ return -1;
+ }
+
+ return 0;
+}
+
+static PyModuleDef_Slot _whirlpoolmodule_slots[] = {
+ {Py_mod_exec, whirlpool_exec},
+#ifdef Py_MOD_PER_INTERPRETER_GIL_SUPPORTED
+ {Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
+#endif
+#ifdef Py_MOD_GIL_NOT_USED
+ {Py_mod_gil, Py_MOD_GIL_NOT_USED},
+#endif
+ {0, NULL},
+};
+
 static PyModuleDef moduledef = {
  PyModuleDef_HEAD_INIT,
  .m_name = "_whirlpool",
  .m_doc = "Reference Whirlpool implementation",
- .m_size = -1,
+ .m_size = 0,
+ .m_slots = _whirlpoolmodule_slots,
 };
 
 PyMODINIT_FUNC
 PyInit__whirlpool(void)
 {
- PyObject *m;
- if (PyType_Ready(&WhirlpoolType) < 0)
- return NULL;
-
- m = PyModule_Create(&moduledef);
- if (m == NULL)
- return NULL;
-
- Py_INCREF(&WhirlpoolType);
- if (PyModule_AddObject(m, "Whirlpool", (PyObject *) &WhirlpoolType) < 0) {
- Py_DECREF(&WhirlpoolType);
- Py_DECREF(m);
- return NULL;
- }
-
- return m;
+ return PyModuleDef_Init(&moduledef);
 }