Add an algorithm (from Couvreur) working on BDDs to reduce the

size of TGBAs represented as BDDs by deleting unaccepting SCCs.

* src/eltlparse/eltlparse.yy: Remove a warning.
* src/tgba/tgbabddconcrete.cc, src/tgba/tgbabddconcrete.hh,
src/tgba/tgbabddcoredata.cc, src/tgba/tgbabddcoredata.hh: Add a
new function delete_unaccepting_scc in both classes.
* src/tgbatest/eltl2tgba.cc, src/tgbatest/spotlbtt.test: Use this
new function in LaCIM for ELTL and bench it.
* src/tgbatest/defs.in: Fix it.
* bench/ltl2tgba/algorithms, bench/ltl2tgba/defs.in: Add LaCIM for
ELTL in benchs.

src/tgba/tgbabddcoredata.hh

@@ -142,6 +142,13 @@ namespace spot
     /// \brief Update the variable sets to take a new acceptance condition
     /// into account.
     void declare_acceptance_condition(bdd prom);
+
+    /// \brief Delete SCCs (Strongly Connected Components) from the
+    /// relation which cannot be accepting.
+    void delete_unaccepting_scc(bdd init);
+
+  private:
+    bdd infinitely_often(bdd s, bdd acc, bdd er);
   };
 }