[API] Add hb_*_get_empty() for all objects
diff --git a/src/hb-buffer.cc b/src/hb-buffer.cc
index 6d0d4d4..7e79eef 100644
--- a/src/hb-buffer.cc
+++ b/src/hb-buffer.cc
@@ -153,6 +153,12 @@
 }
 
 hb_buffer_t *
+hb_buffer_get_empty (void)
+{
+  return &_hb_buffer_nil;
+}
+
+hb_buffer_t *
 hb_buffer_reference (hb_buffer_t *buffer)
 {
   return hb_object_reference (buffer);