ac-wait: import from ~/test.c
ac-wait: clean up
ac-wait: revert cleanup as initial check was needed

This reverts commit 3ab8190abe635c95ca5d785b9d4b5c13fc37afb2.
ac-wait: convert macro to inline function
ac-wait: convert is_one(char) to is_online(udev_device)
git-new: allow specifying more refs

e.g. `git new HEAD dvdhrm/console`