Fix a typo from last time, and Isaac Dunham's todo list:

Fix a typo from last time, and Isaac Dunham's todo list:

  - per POSIX, 'cannot open' must be in the 'type' string if open() fails
  (both EPERM and ENOENT); we only do that if open() succeeds and fstat(fd)
  fails.
  - symlink detection (as per POSIX) won't work: opening them O_RDONLY
  results in following the link, then we fstat() the fd.
  - file 'FIFO' causes a hang; open() won't return till there's a writer.