Fixed potential crash: v can be NULL here, so use Py_XDECREF rather than Py_DECREF
diff --git a/Python/modsupport.c b/Python/modsupport.c
index 98b0341..a2a095e 100644
--- a/Python/modsupport.c
+++ b/Python/modsupport.c
@@ -78,7 +78,7 @@
 	if (doc != NULL) {
 		v = PyString_FromString(doc);
 		if (v == NULL || PyDict_SetItemString(d, "__doc__", v) != 0) {
-			Py_DECREF(v);
+			Py_XDECREF(v);
 			return NULL;
 		}
 		Py_DECREF(v);