Do make your ports remove empty directories when they are de-installed. This is usually accomplished by adding @dirrm lines for all directories that are specifically created by the port. You need to delete subdirectories before you can delete parent directories.

However, sometimes @dirrm will give you errors because other ports share the same directory. You can use @dirrmtry to remove only empty directories without warning.

This will neither print any error messages nor cause pkg_delete(1) to exit abnormally even if ${PREFIX}/share/doc/gimp is not empty due to other ports installing some files in there.

Empty directories created during port installation need special attention. They will not get created when installing the package, because packages only store the files, and pkg_add(1) creates directories for them as needed. To make sure the empty directory is created when installing the package, add this line to pkg-plist above the corresponding @dirrm line: