gh-129345: null check for indent syslogmodule (#129348)

Author: wooffie

Misc/NEWS.d/next/Core_and_Builtins/2025-01-28-06-23-59.gh-issue-129345.uOjkML.rst

@@ -0,0 +1 @@
+Fix null pointer dereference in :func:`syslog.openlog` when an audit hook raises an exception.

Modules/syslogmodule.c

@@ -176,7 +176,7 @@ syslog_openlog_impl(PyObject *module, PyObject *ident, long logopt,
         }
     }
     if (PySys_Audit("syslog.openlog", "Oll", ident ? ident : Py_None, logopt, facility) < 0) {
-        Py_DECREF(ident);
+        Py_XDECREF(ident);
         return NULL;
     }