* src/tgbaalgos/scc.hh (scc_map::~scc_map): Declare it.
* src/tgbaalgos/scc.cc (scc_map::~scc_map): Implement it.
(scc_map::build_map): Delete duplicate states.
* src/tbbatest/ltl2tgba.test: Run ltl2tgba -FV to catch
memory leaks with valgrind.