When emerging postgresql-base, the psql tool is installed, and when trying to select a not tiny set of data, one gets the following error: test=> select * from information_schema.sequences; sh: /usr/bin/less: No such file or directory I just emerged less, and the problem disappeared ... I don't know if someone else got the problem, I can join the /etc/make.conf if needed.
The vast majority of users have 'less' installed. And it was a part of the system set. You are correct, the ebuild does now need to explicitly depend on 'less'.
After a chat with darkside, I've learned that virtual/pager is in the @system set. virtual/pager will pull in a suitable pager for psql.