o Don't free the second list in Lst_Concat for LST_CONCLINK; free
it in the caller instead.
o Remove return value from Lst_Concat. None of the callers ever
checked it. Remove stuff that was needed for circular lists.
o Don't check the return code from Lst_Remove. There is no way that
the list's first element is not on the list.
o No caller checks the return code from Lst_Remove, so don't return
one. Simplify the algorithm now that circular lists are gone.
o Now that circular lists are gone remove stuff for them. Simplify
somewhat so that we can remove a local variable.
Taken-from: FreeBSD
Author: harti