Attached patch-Makefile.diff make this port PREFIX-clean.
Grog maybe you could apply it and release a new version for this port ?
Else it could be placed as files/patch-Makefile.diff under the port directory
in our CVS tree.
Use MAN1 (and MANCOMPRESSED=yes) to make portlint happy
and remove the file from pkg-plist. Since a single file remains put it in
PLIST_FILES variable and drop pkg-plist entirely.
Over to maintainer