diff --git a/env_unix.go b/env_unix.go
index 0fd4bdb..411d438 100644
--- a/env_unix.go
+++ b/env_unix.go
@@ -1,3 +1,4 @@
+//go:build darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
 // +build darwin dragonfly freebsd linux netbsd openbsd solaris
 
 package env