minor, provide diff output (from the diff tool) when the output differs

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
test, provide regression for diff'ing output

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

* feat/diff:
  test, provide regression for diff'ing output
  minor, provide diff output (from the diff tool) when the output differs
hygiene, allow loop around waitpid() to return quickly

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

* code/hygiene:
  hygiene, allow loop around waitpid() to return quickly