vendors/tempy.js/realpath
    function realpath(p, cache, cb) {
      if (ok) {
        return origRealpath(p, cache, cb);
      }
      if (typeof cache === "function") {
        cb = cache;
        cache = null;
      }
      origRealpath(p, cache, function(er, result) {
        if (newError(er)) {
          old.realpath(p, cache, cb);
        } else {
          cb(er, result);
        }
      });
    }