veyron/profiles/roaming: Add missing build tag and comment.
Change-Id: I1b02cdbbff75427b0e6bc3f675da813f0df76256
diff --git a/profiles/roaming/roaminginit.go b/profiles/roaming/roaminginit.go
index 98e74ee..02ac31d 100644
--- a/profiles/roaming/roaminginit.go
+++ b/profiles/roaming/roaminginit.go
@@ -1,3 +1,13 @@
+// +build linux darwin
+
+// Package roaming provides a network-aware Profile that provides appropriate
+// options and configuration for a variety of network configurations, including
+// being behind 1-1 NATs, using dhcp and auto-configuration for being on
+// Google Compute Engine.
+//
+// The config.Publisher mechanism is used for communicating networking
+// settings to the ipc.Server implementation of the runtime and publishes
+// the Settings it expects.
package roaming
import (
