The optstring* helpers do the assignment, which isn't particularly easy
for shellcheck to deduce. So silence the warnings.
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
The arg was never set. Furthermore as-is shellcheck cannot realistically
evaluate the included source.
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
This prevents some odd interactions with the EXIT trap, and our last
command's status is seemingly not preserved for the script's real exit.
Add a BASH override to the Makefile as well, as it might be useful for
debugging or testing against other versions of bash.
