Do check your work with portlint before you submit or commit it. portlint warns you about many common errors, both functional and stylistic. For a new (or repocopied) port, portlint -A is the most thorough; for an existing port, portlint -C is sufficient.
Since portlint uses heuristics to try to figure out errors, it can produce false positive warnings. In addition, occasionally something that is flagged as a problem really cannot be done in any other way due to limitations in the ports framework. When in doubt, the best thing to do is ask on FreeBSD ports 郵遞論壇.