diff --git a/msgp/purego.go b/msgp/purego.go
index 2cd35c3e..fe872341 100644
--- a/msgp/purego.go
+++ b/msgp/purego.go
@@ -1,5 +1,5 @@
-//go:build purego || appengine
-// +build purego appengine
+//go:build (purego && !unsafe) || appengine
+// +build purego,!unsafe appengine
 
 package msgp
 
diff --git a/msgp/unsafe.go b/msgp/unsafe.go
index 06e8d843..7d36bfb1 100644
--- a/msgp/unsafe.go
+++ b/msgp/unsafe.go
@@ -1,5 +1,5 @@
-//go:build !purego && !appengine
-// +build !purego,!appengine
+//go:build (!purego && !appengine) || (!appengine && purego && unsafe)
+// +build !purego,!appengine !appengine,purego,unsafe
 
 package msgp