o Don't free the second list in Lst_Concat for LST_CONCLINK; free

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