- install sbopkg (http://www.sbopkg.org)

create a file /etc/sbopkg/repos.d/70-slackbuilds.repo with this content (one line)

slackbuilds master "Official master git branch from SlackBuilds.org" custom git git://slackbuilds.org/slackbuilds.git@master ""

- to have it selected as the default repository, edit the lines of /etc/sbopkg/sbopkg.conf with the variables REPO_BRANCH and REPO_NAME

REPO_BRANCH=${REPO_BRANCH:-master}
REPO_NAME=${REPO_NAME:-slackbuilds}

and do a sbopkg -r (to sync).

- for temporary usage (after having created the file above in /etc/sbopkg/repos.d/)

sbopkg -V slackbuilds/master -r

sbopkg -V slackbuilds/master -i my_package_or_queue

would do.