- fuzz alf and unalf with afl++ or similar. this is a work in progress,
  fuzzing takes a long time.

- clean up crunch.c.

- figure out why unalf craps out when extracting files of 15MB
  but works fine for 14MB. when this happens, there's no error,
  but the extracted file is like 7KB (and has the correct data
  for the first 7KB of the file). this could be a bug in either
  alf or unalf. I'll have to try it with LZ/DZ in an emulator
  (with 'turbo speed' on, or else it'll take days).

- same issue as above: when using junk from /dev/urandom, the threshold
  is closer to 5MB. it's caused by the exit(0) in asmcode.c. not sure
  under what conditions it should happen (yet).

- write a formal spec of the alf compression stream format?