To avoid causing segmentation faults when input/1 is called in a
jq_state on which jq_set_input_cb() has not been called; e.g. the one
used by jq --run-tests.
That segfault could also be fixed in run_jq_tests() by calling:
jq_set_input_cb(jq, NULL, NULL);
But I think it makes sense to just make jq_init() initialise those
values to NULL.
Ref: https://github.com/jqlang/jq/pull/2717#discussion_r1264338841
Emanuele Torre
e79335e3a5