In PR 64393 the x11-themes/gnome-icons-* ports were noted as having
the following problem:
The last line of a non-slave ports Makefile must be one of:
Attached patch fixes this problem in the following ports:
The patch also renames Makefile.icons to bsd.gome-icons.mk in
x11-themes/gnome-icons to make it apparent to everyone that it is used
like the bsd.*.mk files in /usr/ports/Mk.