message: Add zone1970.tab to the list of files
  that should be ignored by init_tzdb() under USE_OS_TZDB.
diff: @@ -2353,7 +2353,8 @@ init_tzdb()
  strcmp(d->d_name, "iso3166.tab") == 0 ||
  strcmp(d->d_name, "right") == 0 ||
  strcmp(d->d_name, "+VERSION") == 0 ||
  - strcmp(d->d_name, "zone.tab") == 0 )
  + strcmp(d->d_name, "zone.tab") == 0 ||
  + strcmp(d->d_name, "zone1970.tab") == 0 )
  continue;
  auto subname = dirname + folder_delimiter + d->d_name;
  if(stat(subname.c_str(), &s) == 0)
  