diff --git a/agent/docker_unix.go b/agent/docker_unix.go
index 529a5ead18..927733af40 100644
--- a/agent/docker_unix.go
+++ b/agent/docker_unix.go
@@ -1,3 +1,5 @@
+// +build linux freebsd solaris openbsd darwin
+
 package agent
 
 const DefaultDockerHost = "unix:///var/run/docker.sock"