* src/ltlast/Makefile.am: Include lib/ in search path.
* src/ltlast/atomic_prop.cc, src/ltlast/automatop.cc,
src/ltlast/binop.cc, src/ltlast/bunop.cc,
src/ltlast/constant.cc, src/ltlast/formula_tree.cc,
src/ltlast/multop.cc, src/ltlast/nfa.cc,
src/ltlast/refformula.cc, src/ltlast/unop.cc: Include
config.h.