diff --git a/Include/objimpl.h b/Include/objimpl.h
index 2a365d9e016..2410d454003 100644
--- a/Include/objimpl.h
+++ b/Include/objimpl.h
@@ -262,6 +262,8 @@ typedef struct _gc_head {
 /* Get the object given the PyGC_Head */
 #define PyObject_FROM_GC(g) ((PyObject *)(((PyGC_Head *)g)+1))
 
+extern DL_IMPORT(void) PyGC_Dump(PyGC_Head *);
+
 #endif /* WITH_CYCLE_GC */
 
 #ifdef __cplusplus