Check return result from Py_InitModule*().  This API can fail.

Probably should be backported.
diff --git a/Modules/errnomodule.c b/Modules/errnomodule.c
index e9c0990..696d396 100644
--- a/Modules/errnomodule.c
+++ b/Modules/errnomodule.c
@@ -57,6 +57,8 @@
 {
 	PyObject *m, *d, *de;
 	m = Py_InitModule3("errno", errno_methods, errno__doc__);
+	if (m == NULL)
+		return;
 	d = PyModule_GetDict(m);
 	de = PyDict_New();
 	if (!d || !de || PyDict_SetItemString(d, "errorcode", de) < 0)