[spilk]

USB-C does natively support DisplayPort as an alternate mode.

Whether your particular device does is not a given, though. the 12" MacBook definitely does, the specs specifically call out the native support:

http://www.apple.com/macbook/specs/

The specs for the MacBook Pro also purport DisplayPort capability:

http://www.apple.com/macbook-pro/specs/

[prodigal_erik]

DisplayPort is one of several options, but I wouldn't call them native because you can't rely on any of them being supported.