diff --git a/libgrust/libproc_macro/proc_macro.cc b/libgrust/libproc_macro/proc_macro.cc
index d13276294aa..03beb89a33e 100644
--- a/libgrust/libproc_macro/proc_macro.cc
+++ b/libgrust/libproc_macro/proc_macro.cc
@@ -1,7 +1,23 @@
-#include "proc_macro.h"
+// Copyright (C) 2023 Free Software Foundation, Inc.
+//
+// This file is part of the GNU Proc Macro Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
 
-int
-test ()
-{
-  return 0;
-}
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+#include "proc_macro.h"
diff --git a/libgrust/libproc_macro/proc_macro.h b/libgrust/libproc_macro/proc_macro.h
index 2c96b3de685..27c27dbd41a 100644
--- a/libgrust/libproc_macro/proc_macro.h
+++ b/libgrust/libproc_macro/proc_macro.h
@@ -1,7 +1,26 @@
+// Copyright (C) 2023 Free Software Foundation, Inc.
+//
+// This file is part of the GNU Proc Macro Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
 #ifndef PROC_MACRO_H
 #define PROC_MACRO_H
 
-int
-test ();
-
 #endif /* ! PROC_MACRO_H */