Bundle <sys/queue.h> from NetBSD

We are bundling this to allow building on musl-based systems since musl
does not include <sys/queue.h>.
helpers.h, start-stop-daemon.c: remove uneeded macros

TAILQ_CONCAT, TAILQ_FOREACH_SAFE and LIST_FOREACH_SAFE are defined
in our bundled queue.h and are no longer required.