ulrich@gupu:~/inst/ciao$ build/bin/ciao
Ciao 1.15-master-ga7cc57a (2016-11-15 07:37:51 +0100) [LINUXx86_64]
?- use_package(clpfd).
{Using package /home/ulrich/inst/ciao/contrib/library/clpfd/clpfd.pl
{Including /home/ulrich/inst/ciao/contrib/library/clpfd/clpfd_ops.pl
}
}

yes
?- X in 1..2.