- embed version (-D for C code, rst for the man page).

- be more informative with -t option ("No errors found", or "2 files
  with bad checksums found").

- replace all uses of strcpy() with strncpy(), check the filename
  in the archive (make sure it's not missing its null terminator).
  old habits die hard...

- sanity-check the filenames and sizes in alf headers. Atari filenames
  can't be lowercase, start with a number, have two dots... these would
  be warnings, not fatal errors.

- create some alf archives and hexedit them to introduce errors, make
  sure unalf doesn't segfault or get stuck in a loop (it should
  *always* exit cleanly).

- reverse-engineer the ALF14.COM binary, so we have a compressor.
  this would be more of "just to say I did it" thing, there's no real
  need for it.