footprint always ran its dry run with the default 60 second limit, so
macro.run with timeLimit 5 could run for over two minutes (a dry run,
then another after a shift) and fail with "ran longer than 60 seconds".
footprint now takes the run's clock and limit. make_way starts the
run's clock before the dry runs, so the checks and the run share one
limit, and macro.check takes timeLimit too.