local portindex failing on net/tcpflow - macosx_deployment_target

[Adam Mercer]

Hi

In my local ports repository, portindex is failing when running on
net/tcpflow with the following error:

Error: Error executing darwin_9: invalid command name "macosx_deployment_target"
Failed to parse file net/tcpflow/Portfile: Error evaluating variants

Any idea why this is happening in my local ports repository, yet not
in the master repository? I'm running the latest 1.520 release.

Cheers

Adam