Merge branch 'jn/merge-diff3-label'

* jn/merge-diff3-label: merge-recursive: add a label for ancestor cherry-pick, revert: add a label for ancestor revert: clarify label on conflict hunks compat: add mempcpy() checkout -m --conflict=diff3: add a label for ancestor merge_trees(): add ancestor label parameter for diff3-style output merge_file(): add comment explaining behavior wrt conflict style checkout --conflict=diff3: add a label for ancestor ll_merge(): add ancestor label parameter for diff3-style output merge-file --diff3: add a label for ancestor xdl_merge(): move file1 and file2 labels to xmparam structure xdl_merge(): add optional ancestor label to diff3-style output tests: document cherry-pick behavior in face of conflicts tests: document format of conflicts from checkout -m Conflicts: builtin/revert.c