port to bullseye: replace tempfile with mktemp
According to the tempfile(1) manpage:
-d, --directory DIR
Place the file in DIR.
... but in mktemp(1):
-d, --directory
create a directory, not a file
[...]
-p DIR, --tmpdir[=DIR]
interpret TEMPLATE relative to DIR; if DIR is not specified, use
$TMPDIR if set, else /tmp. With this option, TEMPLATE must not
be an absolute name; unlike with -t, TEMPLATE may contain
slashes, but mktemp creates only the final component
The mktemp usage is surprisingly obtuse, to be honest, but I think that's about it: -d is now -p. We don't specify a TEMPLATE so the remark about that shouldn't matter here.
The script is still not "shellcheck-clean" (there's a warning about the trap), but it should fix the immediate problem, which is:
Closes: #3 (closed)