builtin: migrate to SPDX identifier

Most tools used for compliance and SBOM generation use SPDX identifiers
This change brings us a step closer to an easy SBOM generation.

Signed-off-by: Alin Jerpelea <[email protected]>

Author: jerpelea

builtin/CMakeLists.txt

@@ -1,6 +1,8 @@
 # ##############################################################################
 # apps/builtin/CMakeLists.txt
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 # Licensed to the Apache Software Foundation (ASF) under one or more contributor
 # license agreements.  See the NOTICE file distributed with this work for
 # additional information regarding copyright ownership.  The ASF licenses this

builtin/Make.defs

@@ -1,6 +1,8 @@
 ############################################################################
 # apps/builtin/Make.defs
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 # Licensed to the Apache Software Foundation (ASF) under one or more
 # contributor license agreements.  See the NOTICE file distributed with
 # this work for additional information regarding copyright ownership.  The

builtin/Makefile

@@ -1,6 +1,8 @@
 ############################################################################
 # apps/builtin/Makefile
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 # Licensed to the Apache Software Foundation (ASF) under one or more
 # contributor license agreements.  See the NOTICE file distributed with
 # this work for additional information regarding copyright ownership.  The

builtin/builtin_list.c

@@ -1,6 +1,8 @@
 /****************************************************************************
  * apps/builtin/builtin_list.c
  *
+ * SPDX-License-Identifier: Apache-2.0
+ *
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.  The
@@ -29,6 +31,8 @@
 
 #include <sys/stat.h>
 
+#include "builtin_proto.h"
+
 /****************************************************************************
  * Private Types
  ****************************************************************************/
@@ -41,8 +45,6 @@
  * Public Data
  ****************************************************************************/
 
-#include "builtin_proto.h"
-
 const struct builtin_s g_builtins[] =
 {
 #  include "builtin_list.h"

builtin/exec_builtin.c

@@ -1,6 +1,8 @@
 /****************************************************************************
  * apps/builtin/exec_builtin.c
  *
+ * SPDX-License-Identifier: Apache-2.0
+ *
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.  The