reachable.hon commit t4012-diff-binary.sh: use the $( ... ) construct for command substitution (e6ce6f4)
   1#ifndef REACHEABLE_H
   2#define REACHEABLE_H
   3
   4struct progress;
   5extern void mark_reachable_objects(struct rev_info *revs, int mark_reflog, struct progress *);
   6
   7#endif