fail_stack_elt_t
fail_stack_elt_t *stack;
fail_stack.stack = (fail_stack_elt_t *) \
REGEX_ALLOCATE (INIT_FAILURE_ALLOC * sizeof (fail_stack_elt_t)); \
: ((fail_stack).stack = (fail_stack_elt_t *) \
(fail_stack).size * sizeof (fail_stack_elt_t), \
((fail_stack).size << 1) * sizeof (fail_stack_elt_t)), \
fail_stack.stack[fail_stack.avail++] = (fail_stack_elt_t) item
DEBUG_STATEMENT (fail_stack_elt_t failure_id;) \
fail_stack_elt_t word;