diff --git a/internal/xor/xor_generic.go b/internal/xor/xor_generic.go
index 9f76174..490816f 100644
--- a/internal/xor/xor_generic.go
+++ b/internal/xor/xor_generic.go
@@ -1,7 +1,7 @@
 // Copyright 2013 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
-
+//go:build !amd64
 // +build !amd64
 
 package xor
diff --git a/smx509/root_bsd.go b/smx509/root_bsd.go
index 55a9ea9..5d1256d 100644
--- a/smx509/root_bsd.go
+++ b/smx509/root_bsd.go
@@ -1,3 +1,4 @@
+//go:build dragonfly || freebsd || netbsd || openbsd
 // +build dragonfly freebsd netbsd openbsd
 
 package smx509
diff --git a/smx509/root_js.go b/smx509/root_js.go
index 148fd40..55c2354 100644
--- a/smx509/root_js.go
+++ b/smx509/root_js.go
@@ -1,3 +1,4 @@
+//go:build js && wasm
 // +build js,wasm
 
 package smx509
diff --git a/smx509/root_plan9.go b/smx509/root_plan9.go
index 11c7487..84d8a95 100644
--- a/smx509/root_plan9.go
+++ b/smx509/root_plan9.go
@@ -1,3 +1,4 @@
+//go:build plan9
 // +build plan9
 
 package smx509
diff --git a/smx509/root_unix.go b/smx509/root_unix.go
index a6cbeeb..3debd99 100644
--- a/smx509/root_unix.go
+++ b/smx509/root_unix.go
@@ -1,3 +1,4 @@
+//go:build aix || dragonfly || freebsd || (js && wasm) || linux || netbsd || openbsd || solaris
 // +build aix dragonfly freebsd js,wasm linux netbsd openbsd solaris
 
 package smx509