* Properly parse (no) command-line options.
* Ensure that errors go to stderr and result in a non-zero exit.
* Drop the special-case code for a single argument, as it will produce
the wrong outcome if the file does not exist or is corrupted.
* Always create all temporary files before setting the trap. This
ensures that the trap can safely fire at any moment, regardless of any
previous definition of `T`.
* Use a temporary file rather than a pipe between `nm` and `sed` to
ensure proper termination if `nm` fails due to a missing or invalid
input.
* The check for self-referential entries was conditional on testing our
argument list against a regex looking for archives. This was a
needless and unreliable optimization; make the check unconditional.
* Document that lorder will not work properly if any of its inputs have
spaces in their name.
MFC after: 1 week
Sponsored by: Klara, Inc.