message: fix cargo not doing anything when the input and output mtimes are equal
  That's a problem as the input may have changed in that same second but after the output got generated!
diff: @@ -744,7 +744,11 @@ where
  return true;
  }
  };
  - if mtime2 > mtime {
  + // Equal mtimes could mean that the input was changed in that same second,
  + // but *after* the output was generated. So this means they are stale.
  + // In theory, cargo is using nanosecond precision throughout so this
  + // should not make a difference -- but it was necessary to fix #5918.
  + if mtime2 >= mtime {
  info!("stale: {} -- {} vs {}", path.display(), mtime2, mtime);
  true
  } else {
  