minizinc 2.5.0 does not use fzn_alldifferent_except_0 #414

Past versions of minizinc translated alldifferent_except_0 to fzn_alldifferent_except_0 which several solvers implement. The constraint library of minizinc 2.5.0, however, translates alldifferent_except_0 to fzn_alldifferent_except, bypassing any definition of fzn_alldifferent_except_0.

Is this change intentional or accidental? (It was introduced by fd57ce5.)

In order to keep the improved default decomposition of alldifferent_except_0 and, at the same time, to allow for solver-specific definitions of fzn_alldifferent_except_0, I suggest to revert the change to the definition of alldifferent_except_0 and to translate fzn_alldifferent_except_0 to fzn_alldifferent_except.