Issue #10333: Remove ancient GC API, which has been deprecated since
Python 2.2.
diff --git a/Modules/pyexpat.c b/Modules/pyexpat.c
index 1a00347..c83639c 100644
--- a/Modules/pyexpat.c
+++ b/Modules/pyexpat.c
@@ -1522,7 +1522,7 @@
 static PyTypeObject Xmlparsetype = {
         PyVarObject_HEAD_INIT(NULL, 0)
         "pyexpat.xmlparser",            /*tp_name*/
-        sizeof(xmlparseobject) + PyGC_HEAD_SIZE,/*tp_basicsize*/
+        sizeof(xmlparseobject),         /*tp_basicsize*/
         0,                              /*tp_itemsize*/
         /* methods */
         (destructor)xmlparse_dealloc,   /*tp_dealloc*/