Corresponding USE statements should be advised in all cases when such USE is equivalent to dependency. devel/bison is one example I encountered, please make sure the rest are also handled.
This has been added to 2.17.7.
A commit references this bug: Author: marcus Date: Wed Mar 29 15:28:56 UTC 2017 New revision: 437207 URL: https://svnweb.freebsd.org/changeset/ports/437207 Log: Update to 2.17.7. * Fold in the same removal of the obsolete HTTP-only warning * Add support for checking for direct dependency on bison, fmake, and libexecinfo. [1] PR: 216268 [1] Changes: head/ports-mgmt/portlint/Makefile head/ports-mgmt/portlint/src/portlint.pl