Issue #18756: os.urandom() now uses a lazily-opened persistent file descriptor, so as to avoid using many file descriptors when run in parallel from multiple threads.
diff --git a/Include/pythonrun.h b/Include/pythonrun.h
index aca5915..8fdb5b5 100644
--- a/Include/pythonrun.h
+++ b/Include/pythonrun.h
@@ -246,6 +246,7 @@
PyAPI_FUNC(void) _PyGC_Fini(void);
PyAPI_FUNC(void) PySlice_Fini(void);
PyAPI_FUNC(void) _PyType_Fini(void);
+PyAPI_FUNC(void) _PyRandom_Fini(void);
PyAPI_DATA(PyThreadState *) _Py_Finalizing;
#endif