libs/libxx: 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 <alin.jerpelea@sony.com>
diff --git a/libs/libxx/CMakeLists.txt b/libs/libxx/CMakeLists.txt
index 6dacc93..be615f4 100644
--- a/libs/libxx/CMakeLists.txt
+++ b/libs/libxx/CMakeLists.txt
@@ -1,6 +1,8 @@
 # ##############################################################################
 # libs/libxx/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
diff --git a/libs/libxx/Makefile b/libs/libxx/Makefile
index 396c664..622b880 100644
--- a/libs/libxx/Makefile
+++ b/libs/libxx/Makefile
@@ -1,6 +1,8 @@
 ############################################################################
 # libs/libxx/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
diff --git a/libs/libxx/etl.defs b/libs/libxx/etl.defs
index d8de05b..823c05d 100644
--- a/libs/libxx/etl.defs
+++ b/libs/libxx/etl.defs
@@ -1,6 +1,8 @@
 ############################################################################
 # libs/libxx/etl.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
diff --git a/libs/libxx/libcxx.cmake b/libs/libxx/libcxx.cmake
index d8a281c..2e3a63e 100644
--- a/libs/libxx/libcxx.cmake
+++ b/libs/libxx/libcxx.cmake
@@ -1,6 +1,8 @@
 # ##############################################################################
 # libs/libxx/libcxx.cmake
 #
+# 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
diff --git a/libs/libxx/libcxx.defs b/libs/libxx/libcxx.defs
index d703854..50885b3 100644
--- a/libs/libxx/libcxx.defs
+++ b/libs/libxx/libcxx.defs
@@ -1,6 +1,8 @@
 ############################################################################
 # libs/libxx/libcxx.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
diff --git a/libs/libxx/libcxxabi.cmake b/libs/libxx/libcxxabi.cmake
index f55d842..494bb08 100644
--- a/libs/libxx/libcxxabi.cmake
+++ b/libs/libxx/libcxxabi.cmake
@@ -1,6 +1,8 @@
 # ##############################################################################
 # libs/libxx/libcxxabi.cmake
 #
+# 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
diff --git a/libs/libxx/libcxxabi.defs b/libs/libxx/libcxxabi.defs
index 63d780a..e4dd8cd 100644
--- a/libs/libxx/libcxxabi.defs
+++ b/libs/libxx/libcxxabi.defs
@@ -1,6 +1,8 @@
 ############################################################################
 # libs/libxx/libcxxabi.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
diff --git a/libs/libxx/libcxxmini.cmake b/libs/libxx/libcxxmini.cmake
index 3464dbc..a75ed5b 100644
--- a/libs/libxx/libcxxmini.cmake
+++ b/libs/libxx/libcxxmini.cmake
@@ -1,6 +1,8 @@
 # ##############################################################################
 # libs/libxx/libcxxmini.cmake
 #
+# 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
diff --git a/libs/libxx/libcxxmini.defs b/libs/libxx/libcxxmini.defs
index 2624a45..12d137d 100644
--- a/libs/libxx/libcxxmini.defs
+++ b/libs/libxx/libcxxmini.defs
@@ -1,6 +1,8 @@
 ############################################################################
 # libs/libxx/libcxxmini.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
diff --git a/libs/libxx/libcxxmini/libxx_cxa_guard.cxx b/libs/libxx/libcxxmini/libxx_cxa_guard.cxx
index 98fd2d2..ea7bac6 100644
--- a/libs/libxx/libcxxmini/libxx_cxa_guard.cxx
+++ b/libs/libxx/libcxxmini/libxx_cxa_guard.cxx
@@ -1,6 +1,8 @@
 //***************************************************************************
 // libs/libxx/libcxxmini/libxx_cxa_guard.cxx
 //
+// 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
diff --git a/libs/libxx/libcxxmini/libxx_cxapurevirtual.cxx b/libs/libxx/libcxxmini/libxx_cxapurevirtual.cxx
index 69bb454..d9a1223 100644
--- a/libs/libxx/libcxxmini/libxx_cxapurevirtual.cxx
+++ b/libs/libxx/libcxxmini/libxx_cxapurevirtual.cxx
@@ -1,6 +1,8 @@
 //***************************************************************************
 // libs/libxx/libcxxmini/libxx_cxapurevirtual.cxx
 //
+// 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
diff --git a/libs/libxx/libcxxmini/libxx_delete.cxx b/libs/libxx/libcxxmini/libxx_delete.cxx
index ba4490d..11ee18e 100644
--- a/libs/libxx/libcxxmini/libxx_delete.cxx
+++ b/libs/libxx/libcxxmini/libxx_delete.cxx
@@ -1,6 +1,8 @@
 //***************************************************************************
 // libs/libxx/libcxxmini/libxx_delete.cxx
 //
+// 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
diff --git a/libs/libxx/libcxxmini/libxx_delete_sized.cxx b/libs/libxx/libcxxmini/libxx_delete_sized.cxx
index 359d2cd..b2148cd 100644
--- a/libs/libxx/libcxxmini/libxx_delete_sized.cxx
+++ b/libs/libxx/libcxxmini/libxx_delete_sized.cxx
@@ -1,6 +1,8 @@
 //***************************************************************************
 // libs/libxx/libcxxmini/libxx_delete_sized.cxx
 //
+// 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
diff --git a/libs/libxx/libcxxmini/libxx_deletea_sized.cxx b/libs/libxx/libcxxmini/libxx_deletea_sized.cxx
index 0a7fc8b..ab1dda9 100644
--- a/libs/libxx/libcxxmini/libxx_deletea_sized.cxx
+++ b/libs/libxx/libcxxmini/libxx_deletea_sized.cxx
@@ -1,6 +1,8 @@
 //***************************************************************************
 // libs/libxx/libcxxmini/libxx_deletea_sized.cxx
 //
+// 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
diff --git a/libs/libxx/libcxxmini/libxx_new.cxx b/libs/libxx/libcxxmini/libxx_new.cxx
index be78cc7..8416feb 100644
--- a/libs/libxx/libcxxmini/libxx_new.cxx
+++ b/libs/libxx/libcxxmini/libxx_new.cxx
@@ -1,6 +1,8 @@
 //***************************************************************************
 // libs/libxx/libcxxmini/libxx_new.cxx
 //
+// 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
diff --git a/libs/libxx/libcxxmini/libxx_newa.cxx b/libs/libxx/libcxxmini/libxx_newa.cxx
index f078802..8dbc57f 100644
--- a/libs/libxx/libcxxmini/libxx_newa.cxx
+++ b/libs/libxx/libcxxmini/libxx_newa.cxx
@@ -1,6 +1,8 @@
 //***************************************************************************
 // libs/libxx/libcxxmini/libxx_newa.cxx
 //
+// 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
diff --git a/libs/libxx/system_configuration.h b/libs/libxx/system_configuration.h
index abe1e81..fff4560 100644
--- a/libs/libxx/system_configuration.h
+++ b/libs/libxx/system_configuration.h
@@ -1,6 +1,8 @@
 /****************************************************************************
  * libs/libxx/system_configuration.h
  *
+# 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
diff --git a/libs/libxx/uClibc++.cmake b/libs/libxx/uClibc++.cmake
index 72c3f51..e04b317 100644
--- a/libs/libxx/uClibc++.cmake
+++ b/libs/libxx/uClibc++.cmake
@@ -1,6 +1,8 @@
 # ##############################################################################
 # libs/libxx/uClibc++.cmake
 #
+# 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
diff --git a/libs/libxx/uClibc++.defs b/libs/libxx/uClibc++.defs
index b8f5436..00d92b9 100644
--- a/libs/libxx/uClibc++.defs
+++ b/libs/libxx/uClibc++.defs
@@ -1,6 +1,8 @@
 ############################################################################
 # libs/libxx/uClibc++.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