Merge branch 'nd/attr-pathspec-in-tree-walk'

The traversal over tree objects has learned to honor
":(attr:label)" pathspec match, which has been implemented only for
enumerating paths on the filesystem.

* nd/attr-pathspec-in-tree-walk:
  tree-walk: support :(attr) matching
  dir.c: move, rename and export match_attrs()
  pathspec.h: clean up "extern" in function declarations
  tree-walk.c: make tree_entry_interesting() take an index
  tree.c: make read_tree*() take 'struct repository *'

list-objects.c

@@ -114,7 +114,8 @@ static void process_tree_contents(struct traversal_context *ctx,
 
 	while (tree_entry(&desc, &entry)) {
 		if (match != all_entries_interesting) {
-			match = tree_entry_interesting(&entry, base, 0,
+			match = tree_entry_interesting(ctx->revs->repo->index,
+						       &entry, base, 0,
 						       &ctx->revs->diffopt.pathspec);
 			if (match == all_entries_not_interesting)
 				break;