t / t4101 / diff.3-0on commit fast-import: Introduce --import-marks-if-exists (dded4f1)
   1--- a/frotz
   2+++ b/frotz
   3@@ -1,3 +1,2 @@
   4 a
   5-c
   6-b
   7\ No newline at end of file
   8+b