warnings in groff

[Ted Unangst]

While building vim-no_x11 on arm, I observe:

===>  Building for groff-1.22.2p4
configure: WARNING: unrecognized options: --without-libiconv-prefix,
--without-gs, --without-x, --with-awk, --disable-silent-rules
configure: loading site script /home/tedu/ports/pobj/groff-1.22.2/config.site