levenshtein.hon commit merge-recursive: provide pair of `unpack_trees_{start,finish}()` (3f1c1c3)
   1#ifndef LEVENSHTEIN_H
   2#define LEVENSHTEIN_H
   3
   4int levenshtein(const char *string1, const char *string2,
   5        int swap_penalty, int substitution_penalty,
   6        int insertion_penalty, int deletion_penalty);
   7
   8#endif