Fix build errors on recent macOS versions.

CHANGES.rst

@@ -6,15 +6,15 @@ For changes before version 3.0, see ``HISTORY.rst``.
 6.4 (unreleased)
 ----------------
 
-- Nothing changed yet.
-
 - Make dict views (`.keys()`, `.items()` and `.values()`) behave like their
   unrestricted versions.
   (`#147 <https://github.com/zopefoundation/AccessControl/pull/147>`_)
 
 - Make `.items()` validate each keys and values, like `.keys()` and
   `.values()` do.
 
+- Fix build errors on recent macOS versions.
+
 
 6.3 (2023-11-20)
 ----------------

src/AccessControl/cAccessControl.c

@@ -425,7 +425,7 @@ static PyExtensionClass ZopeSecurityPolicyType = {
 	0,					/* tp_itemsize	*/
 	/* Standard methods 	*/
 	(destructor) ZopeSecurityPolicy_dealloc,/* tp_dealloc	*/
-	NULL,					/* tp_print	*/
+	0,  					/* tp_print	*/
 	NULL,					/* tp_getattr	*/
 	NULL,					/* tp_setattr	*/
 	NULL,					/* tp_compare	*/
@@ -484,7 +484,7 @@ static PyExtensionClass SecurityManagerType = {
 	0,					/* tp_itemsize	*/
 	/* Standard methods 	*/
 	(destructor) SecurityManager_dealloc,/* tp_dealloc	*/
-	NULL,					/* tp_print	*/
+	0,  					/* tp_print	*/
 	NULL,					/* tp_getattr	*/
 	NULL,					/* tp_setattr	*/
 	NULL,					/* tp_compare	*/
@@ -543,7 +543,7 @@ static PyExtensionClass PermissionRoleType = {
 	0,					/* tp_itemsize	*/
 	/* Standard methods 	*/
 	(destructor) PermissionRole_dealloc,	/* tp_dealloc	*/
-	NULL,					/* tp_print	*/
+	0,  					/* tp_print	*/
 	NULL,					/* tp_getattr	*/
 	NULL,					/* tp_setattr	*/
 	NULL,					/* tp_compare	*/
@@ -613,7 +613,7 @@ static PyExtensionClass imPermissionRoleType = {
 	0,					/* tp_itemsize	*/
 	/* Standard methods 	*/
 	(destructor) imPermissionRole_dealloc,	/* tp_dealloc	*/
-	NULL,					/* tp_print	*/
+	0,  					/* tp_print	*/
 	NULL,					/* tp_getattr	*/
 	NULL,	                                /* tp_setattr	*/
 	NULL,					/* tp_compare	*/