test, provide rotz-show regressions

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, provide diff output (from the diff tool) when the output differs

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
hygiene, allow loop around waitpid() to return quickly

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
fix, PEBKAC, always inc jp if *ip in intersection pruner vtxlst_intersection()

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'cmd/show' into next

* cmd/show:
  fix, PEBKAC, always inc jp if *ip in intersection pruner vtxlst_intersection()
  hygiene, allow loop around waitpid() to return quickly
  minor, provide diff output (from the diff tool) when the output differs
  test, provide rotz-show regressions