=> Bootstrap dependency digest>=20010302: found digest-20160304
===> Skipping vulnerability checks.
WARNING: No /var/db/pkg/pkg-vulnerabilities file found.
WARNING: To fix run: `/usr/sbin/pkg_admin -K /var/db/pkg fetch-pkg-vulnerabilities'.
===> Installing for swi-prolog-packages-6.6.6nb1
=> Generating pre-install file lists
=> Creating installation directories
Error: Environment variable DISPLAY must be set
       and point to a connectible X server.
*** Error code 1

Stop.
make[1]: stopped in /data/pkgsrc-current/lang/swi-prolog-packages
*** Error code 1

Stop.
make: stopped in /data/pkgsrc-current/lang/swi-prolog-packages