ports/66565: [PATCH] bsd.port.mk: fix build dependencies whenXFREE86_VERSION == 3

[Mark Linimon]

Basically, this means that I broke XFree86-3 when I removed the
(unused according to INDEX) devel/imake.

The fact that no one has noticed until now (2-3 months later)
probably means that we should consider removing XFree86-3 as well.
I wouldn't be surprised to find that our support for it in various
ports had already failed long before this.