... to prevent linking against libs from build host. I.e. if
Ports/fontconfig is already installed imagemagick tries to
link against it in /usr/local/lib and fails to build.
--host=... will already be passed by ../.port_include.sh
We currently have no valid use case for having a `port` property
different from the directory name the port's residing in. We do have
issues when this is the case when referencing dependencies, so let's
make sure all ports have a sensible `port` property to begin with.