Do not crash when checking semantics of undeclared symbolic_variable.
NOTE: this update may have broken the printing of error messages
during semantic analysis of IL code.

default: runtests


runtests:
	./runtests


clean:
	rm -f *.iec
	rm -f *.err
	rm -f *.err2
	rm -f *.out
	rm -f *.out2