The removed function 'newchain(a, b)' was almost the same as calling
!chain_equal(a, b), varying only in the amount of data compared
in the non-fixed-length data portion of given chain nodes.
A third argument 'data_size' has been introduced into 'chain_equal'
function in order to allow it to know how many bytes to compare in the
variable-length data portion of the chain nodes.
A helper function 'chain_length(e)' has been introduced to allow
easy calculation of the total length of the non-fixed-length data part
of chain nodes.
Check the thread below for more details:
https://gitlab.isc.org/isc-projects/bind9/-/merge_requests/291#note_12184
(cherry picked from commit 37f42d19a1)
Diego FronzaandEvan Hunt
7af2573219