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

Probably should be backported.
diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
index db9dd32..00239bd 100644
--- a/Modules/gcmodule.c
+++ b/Modules/gcmodule.c
@@ -1158,6 +1158,8 @@
 			      gc__doc__,
 			      NULL,
 			      PYTHON_API_VERSION);
+	if (m == NULL)
+		return;
 
 	if (garbage == NULL) {
 		garbage = PyList_New(0);