chore, lose old abstract trod type

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, dynamically switch to heap space in co_tser_flt() when static space is used up

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, use permanent pointers in step system, build a stack of stacks

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, save mod counter over resize to avoid checking for dupes all over again

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
fix, PEBKAC, actually iterate over all stacks of stacks

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
hygiene, discard unused recalloc()

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'core/step'

* core/step:
  hygiene, discard unused recalloc()
  fix, PEBKAC, actually iterate over all stacks of stacks
  minor, save mod counter over resize to avoid checking for dupes all over again
  minor, use permanent pointers in step system, build a stack of stacks
  minor, dynamically switch to heap space in co_tser_flt() when static space is used up
  chore, lose old abstract trod type