Log Message:
Update to 1.4.20. From the changelog:

indexers:

* omindex:

  + OpenDocument: Previously we only inserted an implicit space before each
    paragraph.  Now we insert them both before and after each paragraph and
    heading, and before forced each line-break and tab.

  + Add extension mapping for .awt (Abiword templates).

  + Index metadata from XPS files.

  + -G and -C short options were documented in --help but not previously
    actually handled. Reported by David Bremner.

  + Show --max-size required argument in --help output.

  + Remove lingering handling for database backends without slot bounds since
    all backends have been required to support these since 1.4.11.

* scriptindex:

  + Process an incomplete final line from a dump file.  Previously if the final
    line lacked a newline scriptindex would quietly ignore it (unless it was
    the only line).

  + The `unique` action now takes an optional `missing` parameter to specify
    what to do if a record doesn't trigger the unique action or triggers it
    with an empty value.  The default is now to issue a warning and create a
    new document (the same as before, except that there was only previously a
    warning for the empty value case). In Omega 1.5.0 the default will change
    to an error as that seems a better default, but is less compatible with
    potential existing use.

  + Explicitly allow multiple blank lines in input files.  Previously such
    extra blank lines were treated as empty records and in many cases these
    got quietly skipped, but e.g. with the new UNIQUE checks this could result
    in a warning or error.

  + If we hit an error while parsing the index script we used to exit right
    away, but now we finish parsing the index script since it's more helpful to
    report all the errors in an index script rather than the user having to
    fix them one by one.  This requires us to sensibly recover after each index
    script parse error - if you find a case where this recovery triggers
    further bogus errors please report it and we'll try to improve the
    recovery.

  + In four cases while handling input data (two cases of bad hex data fed
    to `hextobin`, an input data line without a `=`, and `load` failing to
    load the specified file) we'd emit a diagnostic that was labelled as an
    "error" but really it was handled as a warning as we kept reading input
    and the "error" didn't affect the exit status.  It doesn't really make
    sense to continue in any of these cases so we now exit with non-zero status
    right away.

  + A parameter in the index script which should be an integer but isn't, or
    should be positive but isn't now gives an error rather than a warning since
    an error seems more helpful.

  + All diagnostics issued while parsing the index script now include column
    information.

  + Avoid forcibly flushing the output stream after every message.

testsuite:

* Improve test coverage for scriptindex.

portability:

* Require PCRE2 instead of PCRE. The original PCRE is now EOL and unmaintained
  (last release was June 2021).  In omega it's potentially used to process
  input from the internet, so security is a real concern hence we're switching
  to PCRE2.