extern int rev_same_tree_as_empty(struct rev_info *, struct tree *t1);
extern int rev_compare_tree(struct rev_info *, struct tree *t1, struct tree *t2);
-extern void init_revisions(struct rev_info *revs);
+extern void init_revisions(struct rev_info *revs, const char *prefix);
extern int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def);
extern void prepare_revision_walk(struct rev_info *revs);
extern struct commit *get_revision(struct rev_info *revs);