Function unify

gecode/int/gcc.cpp:56–59

Make \a x and \a y equal

    /// Make \a x and \a y equal
    IntVar unify(Home home, IntVar x, IntVar y) {
      rel(home, x, IRT_EQ, y);
      return x;
    }
    /// Make \a x and \a y equal
    IntSet unify(Home, const IntSet& x, const IntSet& y) {
      IntSetRanges xr(x);