autfilt: add --aliases=drop|keep option

* bin/autfilt.cc: Here.
* spot/twaalgos/hoa.cc, spot/twaalgos/hoa.hh: Fix the prototype
of set_aliases so that it is usable.
* tests/core/dualize.test: Add a simple test case.
* NEWS: Mention the new option.

tests/core/dualize.test

@@ -1,6 +1,6 @@
 #!/bin/sh
 # -*- coding: utf-8 -*-
-# Copyright (C) 2017, 2019, 2021 Laboratoire de Recherche et
+# Copyright (C) 2017, 2019, 2021, 2022 Laboratoire de Recherche et
 # Développement de l'Epita (LRDE).
 #
 # This file is part of Spot, a model checking library.
@@ -72,6 +72,10 @@ HOA: v1
 States: 10
 Start: 0&4
 AP: 2 "p0" "p1"
+Alias: @a 0&!1
+Alias: @b !0&!1
+Alias: @c 0&1
+Alias: @d !0&1
 Acceptance: 2 Inf(0) | Inf(1)
 properties: trans-labels explicit-labels trans-acc univ-branch
 --BODY--
@@ -104,7 +108,8 @@ State: 9
 [!0] 9
 --END--
 EOF
-autfilt --dualize <input2 >output2
+autfilt --dualize --aliases=drop <input2 >output2
+autfilt --dualize <input2 >>output2
 cat >expected2<<EOF
 HOA: v1
 States: 9
@@ -140,5 +145,43 @@ State: 8
 [!1] 0&6&7
 [!0&!1] 0&7
 --END--
+HOA: v1
+States: 9
+Start: 8
+AP: 2 "p0" "p1"
+acc-name: co-Buchi
+Acceptance: 1 Fin(0)
+properties: trans-labels explicit-labels state-acc univ-branch
+Alias: @a 0&!1
+Alias: @b !0&!1
+Alias: @c 0&1
+Alias: @d !@c&!@b&!@a
+--BODY--
+State: 0
+[@a] 0&6&7
+[@b] 0&7
+State: 1
+[@c | @a] 1&2&3
+[@d | @b] 1&3
+State: 2
+[@c | @a] 4
+State: 3
+[@c | @a] 4
+[@d | @b] 5
+State: 4
+[t] 4
+State: 5
+[@d | @b] 5
+State: 6 {0}
+[@d | @b] 4
+[@c | @a] 6
+State: 7
+[@b | @a] 7
+State: 8
+[t] 1&2&3
+[@d | @b] 1&3
+[@b | @a] 0&6&7
+[@b] 0&7
+--END--
 EOF
 diff output2 expected2