watchmanctl: make audit run on Windows
watchmanctl: make audit run on Windows

Summary: watchmanctl building was failing because audit wasn't written for Windows. This diff fixes that.

Reviewed By: genevievehelsel

Differential Revision: D30783366

fbshipit-source-id: d927d8e5e97b2b03f77f0ed59134f5a00aac81f6

nodakai/watchman,facebook/watchman,facebook/watchman,facebook/watchman,facebook/watchman,nodakai/watchman,facebook/watchman,facebook/watchman,nodakai/watchman,facebook/watchman,nodakai/watchman,nodakai/watchman,nodakai/watchman,nodakai/watchman,nodakai/watchman,facebook/watchman,nodakai/watchman,facebook/watchman