Bug #1566280: Explicitly invoke threading._shutdown from Py_Main,
to avoid relying on atexit.
Will backport to 2.5.
diff --git a/Modules/main.c b/Modules/main.c
index 2224dfe..dc46d55 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -177,6 +177,33 @@
 	return 0;
 }
 
+/* Wait until threading._shutdown completes, provided
+   the threading module was imported in the first place.
+   The shutdown routine will wait until all non-daemon
+   "threading" threads have completed. */
+#include "abstract.h"
+static void
+WaitForThreadShutdown()
+{
+#ifdef WITH_THREAD
+	PyObject *result;
+	PyThreadState *tstate = PyThreadState_GET();
+	PyObject *threading = PyMapping_GetItemString(tstate->interp->modules,
+						      "threading");
+	if (threading == NULL) {
+		/* threading not imported */
+		PyErr_Clear();
+		return;
+	}
+	result = PyObject_CallMethod(threading, "_shutdown", "");
+	if (result == NULL)
+		PyErr_WriteUnraisable(threading);
+	else
+		Py_DECREF(result);
+	Py_DECREF(threading);
+#endif
+}
+
 /* Main program */
 
 int
@@ -514,6 +541,8 @@
 		/* XXX */
 		sts = PyRun_AnyFileFlags(stdin, "<stdin>", &cf) != 0;
 
+	WaitForThreadShutdown();
+
 	Py_Finalize();
 #ifdef RISCOS
 	if (Py_RISCOSWimpFlag)