Add explicit lint-comment-style fallthrough annotations. GCC now assumes that if you don't have these you're making a mistake, which is annoying. XXX: This changeset updates the AG output files only (by hand) and is XXX: abusive - rebuilding them will erase the change. However, I need XXX: to get things to build before I can try to get AG to issue the XXX: annotations itself, so this seems like a reasonable expedient.

[
  disregard ws
]

file $
  -> thing, eof

thing
  -> '[', "blah ", ']'
  -> word

word
  -> letter
  -> word, letter

ws
  -> space + tab

letter = 'a-z'
space = ' '
tab = '\t'
eof = '\n'