diff --git a/internal/fastabs/filepath_unix.go b/internal/fastabs/filepath_unix.go
index 1dd09994d..8844fcea0 100644
--- a/internal/fastabs/filepath_unix.go
+++ b/internal/fastabs/filepath_unix.go
@@ -1,3 +1,5 @@
+//go:build unix
+
 package fastabs
 
 import (