diff --git a/params_darwin.go b/params_darwin.go
index 13c6b18..bba950e 100644
--- a/params_darwin.go
+++ b/params_darwin.go
@@ -1,3 +1,4 @@
+// +build darwin
 
 package water
 
diff --git a/params_linux.go b/params_linux.go
index cff2f16..8f69d0a 100644
--- a/params_linux.go
+++ b/params_linux.go
@@ -1,3 +1,4 @@
+// +build linux
 
 package water