Portlint doesn't handle new *_DEPENDS syntax without ${PORTSDIR}:
cd /usr/ports/security/courierpassd && portlint WARN: Makefile: no port directory security/courier-authlib-base found, even though it is listed in BUILD_DEPENDS. WARN: Makefile: no port directory security/courier-authlib-base found, even though it is listed in RUN_DEPENDS.
Fix that: while older version replaces '${PORTSDIR}' with real portsdir, after fix it just prepends real portsdir and slash.