Some ports have a rather hardcoded dependency on Subversion and specifically
devel/subversion (vs. devel/subversion-freebsd).
So combine the two - allowing one to build just "subversion" to satisfy
dependencies but with the FreeBSD hacks.
I have not done this via an OPTION as I do not know if we want to expose
"Build with FreeBSD hacks" to all the users of the Subversion port. Instead
it keys off of 'WITH_FREEBSD_SUBVERSION'. If putting this in OPTIONS is the
better approach I can follow up and do that.
Approved by: maintainer timeout