Deprecated `PROG_RET_MAP_HAYSTACK_FAILED`
XXX: Currently `PROG_RET_MATCH_HAYSTACK_N_FAILED(n)` returns `n` verbatim (casted to `int`). Maybe we should ensure the number is nonzero in the macro? Or rework haystack numbers to start at 0 and have this macro add 1 to `n`? The former seems easier.
Fortune for naka's current commit: Middle blessing − 中吉
Added main TODOs in main(), regarding setting up threadpool, dispatches, consolidation, process return value on match fails, etc.
Fortune for naka's current commit: Small blessing − 小吉