build: separate compiler and libs

compiler/internal/lib/runtime/mfinal.go

@@ -0,0 +1,12 @@
+// Copyright 2009 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.
+
+// Garbage collector: finalizers and block profiling.
+
+package runtime
+
+func SetFinalizer(obj any, finalizer any) {
+	// TODO(xsw):
+	// panic("todo: runtime.SetFinalizer")
+}