The --enable-option-checking=fatal option prevents ./configure from
proceeding when an unknown option is used in the ./configure step in CI.
This change will avoid adding unsupported ./configure options or options
with typo or typo in pairwise testing "# [pairwise: ...]" marker.
The size of the log generated by each GitLab CI job is limited to 4 MB
by default. While this limit is configurable, it makes little sense to
print build logs to standard output if they are being captured to files
anyway. Limit use of "tee" in util/pairwise-testing.sh to printing the
combination of configure switches used for a given build. This way the
job should never exceed the default 4 MB log size limit, yet it will
still indicate its progress in a concise way.
Pairwise testing is a test case generation technique based on the
observation that most faults are caused by interactions of at most two
factors. For BIND, its configure options can be thought of as such
factors.
Process BIND configure options into a model that is subsequently
processed by the PICT tool in order to find an effective test vector.
That test vector is then used for configuring and building BIND using
various combinations of configure options.
