gdbm: update to 1.22.

Version 1.22

* Fix file header validation

* Fix key verification in sequential access

* Fix testing with DejaGNU 1.6.3

* Fix stack overflow in print_usage

* Fix a leak of avail entry on pushing a new avail block

The leak would occur if the original avail table had odd number of entries.

* New gdbmtool variables: errorexit, errormask, trace, timing

"Errorexit" and "errormask" control which GDBM errors would cause the
program termination and emitting a diagnostic message,
correspondingly.  Both variables are comma-delimited lists of error
codes.

The "trace" variable enables tracing of the gdbmtool commands.

The "timing" variable, when set, instructs gdbmtool to print time
spent in each command it runs.

* New gdbmtool options: -t (--trace), and -T (--timing)

(wiz)