*
  * Copyright (c) 2006 Junio C Hamano
  */
+#define USE_THE_INDEX_COMPATIBILITY_MACROS
 #include "cache.h"
 #include "config.h"
 #include "lockfile.h"
                              int argc, const char **argv,
                              struct object_array_entry **blob)
 {
-       unsigned mode = canon_mode(S_IFREG | 0644);
+       const unsigned mode = canon_mode(S_IFREG | 0644);
 
        if (argc > 1)
                usage(builtin_diff_usage);
        discard_cache();
        read_cache();
        refresh_cache(REFRESH_QUIET|REFRESH_UNMERGED);
-       update_index_if_able(&the_index, &lock_file);
+       repo_update_index_if_able(the_repository, &lock_file);
 }
 
 static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv)