Introduce a dba_complement() function.

Loosely based on "Complementing Deterministic Büchi Automata in
Polynomial Time", R. P. Kurshan, 1987, J. Comp. Syst. Sci. 35.

* src/tgbaalgos/dbacomp.cc, src/tgbaalgos/dbacomp.hh: New files.
* src/tgbaalgos/Makefile.am: Add them.
* src/tgbatest/ltl2tgba.cc (-DC): New option to test it.

src/tgbaalgos/dbacomp.hh

@@ -0,0 +1,39 @@
+// -*- coding: utf-8 -*-
+// Copyright (C) 2013 Laboratoire de Recherche et Développement
+// de l'Epita.
+//
+// This file is part of Spot, a model checking library.
+//
+// Spot is free software; you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+//
+// Spot is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+// or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+// License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#ifndef SPOT_TGBAALGOS_DBACOMP_HH
+# define SPOT_TGBAALGOS_DBACOMP_HH
+
+#include "tgba/tgbaexplicit.hh"
+
+namespace spot
+{
+
+
+  /// Complement a deterministic Büchi automaton
+  ///
+  /// The automaton \a aut should be deterministic and should have at
+  /// most a single acceptance condition.  It can be transition-based,
+  /// or state-based.  The resulting automaton is very unlikely to be
+  /// deterministic.
+  SPOT_API tgba_explicit_number*
+  dba_complement(const tgba* aut);
+}
+
+#endif // SPOT_TGBAALGOS_DBACOMP_HH