var mo = new Ggit.MergeOptions();
mo.set_file_favor(Ggit.MergeFileFavor.THEIRS);
var ix = this.repo.merge_trees(anc_tree, master_tree, head_tree, mo);
var mo = new Ggit.MergeOptions();
mo.set_file_favor(Ggit.MergeFileFavor.THEIRS);
var ix = this.repo.merge_trees(anc_tree, master_tree, head_tree, mo);