The script takes two file names on the command line: an old tape, and
a new tape. Any updated files are written to a new tape diffs.tap.
The intent is that diffs.tap can be extradted with a DUMP command like
LOAD CRDIR LINKS to update an ITS system.
The script tries to avoid including binary files that only differ in
the symbol table or creation time. Some false positives are expected.
3eb08a071c