How to avoid Xcode license dance

[Ryan Schmidt]

Is there a way -- command line flag or environment variable maybe -- to instruct MacPorts not to do the Xcode license dance where it copies the Xcode plist? I'm having trouble writing a special script which runs multiple `port` commands in parallel because:

error deleting "/opt/local/var/macports/home/Library/Preferences/com.apple.dt.Xcode.plist"

because another process already deleted it.

Alternately, could we instruct MacPorts not to do the Xcode license thing for subcommands that don't have anything to do with Xcode, such as `port info` or `port distfiles`?