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

Probably should be backported.
diff --git a/Modules/regexmodule.c b/Modules/regexmodule.c
index 9f84032..d449932 100644
--- a/Modules/regexmodule.c
+++ b/Modules/regexmodule.c
@@ -653,6 +653,8 @@
 	Regextype.ob_type = &PyType_Type;
 
 	m = Py_InitModule("regex", regex_global_methods);
+	if (m == NULL)
+		return;
 	d = PyModule_GetDict(m);
 
 	if (PyErr_Warn(PyExc_DeprecationWarning,