Ref fixes

from_cpython/Python/_warnings.c

@@ -44,7 +44,7 @@ get_warnings_attr(const char *attr)
     int result;
 
     if (warnings_str == NULL) {
-        warnings_str = PyString_InternFromString("warnings");
+        warnings_str = PyGC_RegisterStaticConstant(PyString_InternFromString("warnings"));
         if (warnings_str == NULL)
             return NULL;
     }
@@ -658,12 +658,12 @@ warnings_warn_explicit(PyObject *self, PyObject *args, PyObject *kwds)
         PyObject *returned;
 
         if (get_source_name == NULL) {
-            get_source_name = PyString_InternFromString("get_source");
+            get_source_name = PyGC_RegisterStaticConstant(PyString_InternFromString("get_source"));
             if (!get_source_name)
                 return NULL;
         }
         if (splitlines_name == NULL) {
-            splitlines_name = PyString_InternFromString("splitlines");
+            splitlines_name = PyGC_RegisterStaticConstant(PyString_InternFromString("splitlines"));
             if (!splitlines_name)
                 return NULL;
         }

src/runtime/types.cpp

@@ -4334,6 +4334,7 @@ void setupRuntime() {
     _PyExc_Init();
     _PyImport_Init();
     _PyImportHooks_Init();
+    _PyWarnings_Init();
 
     PyType_Ready(&PyByteArrayIter_Type);
     PyType_Ready(&PyCapsule_Type);