Update to 20180522.5b12791. From the git log:

- Missing .gitignore rule for autoconf detritus.
- Give a sensible error message about misordered dumps.
- Convert to and from a new 'sortable' dump format.
- Factor out dump-file handling. (NFC)
- Remove unused variables spotted by -Wall.
- Revise parsing of /proc/net/tcp[6] for magic HTTP auth.
- Fix mmap(2) error checks
- Fix pathname-lookup failure on 'agedu -H /'.
- Add a --numeric option, modifying HTML multifile output.

(schmonz)