diff --git a/src/runtime/runtime.go b/src/runtime/runtime.go
index eecedee2..1a2a0495 100644
--- a/src/runtime/runtime.go
+++ b/src/runtime/runtime.go
@@ -95,3 +95,9 @@ func KeepAlive(x interface{}) {
 func SetFinalizer(obj interface{}, finalizer interface{}) {
 	// Unimplemented.
 }
+
+//go:linkname godebug_setUpdate internal/godebug.setUpdate
+func godebug_setUpdate(update func(string, string)) {
+	// Unimplemented. The 'update' function needs to be called whenever the
+	// GODEBUG environment variable changes (for example, via os.Setenv).
+}