diff --git a/merge.go b/merge.go
index 06e98a0..9c804f7 100644
--- a/merge.go
+++ b/merge.go
@@ -126,6 +126,13 @@ const (
 	// continue resolving conflicts.  The merge operation will fail with
 	// GIT_EMERGECONFLICT and no index will be returned.
 	MergeTreeFailOnConflict MergeTreeFlag = C.GIT_MERGE_FAIL_ON_CONFLICT
+	// Do not write the REUC extension on the generated index
+	MergeTreeSkipREUC MergeTreeFlag = C.GIT_MERGE_SKIP_REUC
+	// If the commits being merged have multiple merge bases, do not build
+	// a recursive merge base (by merging the multiple merge bases),
+	// instead simply use the first base.  This flag provides a similar
+	// merge base to `git-merge-resolve`.
+	MergeTreeNoRecursive MergeTreeFlag = C.GIT_MERGE_NO_RECURSIVE
 )
 
 type MergeOptions struct {