Repair mis-application of Jeremy's patch.  Thanks, Neal!
diff --git a/Modules/pyexpat.c b/Modules/pyexpat.c
index 5c3cf25..6c40893 100644
--- a/Modules/pyexpat.c
+++ b/Modules/pyexpat.c
@@ -989,7 +989,7 @@
         int bytes_read;
         void *buf = XML_GetBuffer(self->itself, BUF_SIZE);
         if (buf == NULL) {
-            Py_DECREF(readmethod);
+            Py_XDECREF(readmethod);
             return PyErr_NoMemory();
         }