code: void addTernaryClause(final MiniSatStyleSolver s, int a, int b, int c) {
      this.addTernaryClause(s, a, b, c, LIT_UNDEF);
    }
docs: Adds a ternary clause to the given SAT solver.
  @param s the sat solver
  @param a the first literal
  @param b the second literal
  @param c the third literal