patch 9.1.0831: 'findexpr' can't be used as lambad or Funcref

Problem:  'findexpr' can't be used for lambads
          (Justin Keyes)
Solution: Replace the findexpr option with the findfunc option
          (Yegappan Lakshmanan)

related: #15905
closes: #15976

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/evalbuffer.c b/src/evalbuffer.c
index 6ec734d..cefd642 100644
--- a/src/evalbuffer.c
+++ b/src/evalbuffer.c
@@ -45,6 +45,8 @@
 #endif
 	if (!abort)
 	    abort = abort || set_ref_in_callback(&bp->b_tfu_cb, copyID);
+	if (!abort)
+	    abort = abort || set_ref_in_callback(&bp->b_ffu_cb, copyID);
 	if (abort)
 	    break;
     }