bld: add missing licenses

Signed-off-by: Federico Vaga <federico.vaga@cern.ch>

lib/.gitignore

+# SPDX-License-Identifier: CC0-1.0
+#
+# SPDX-FileCopyrightText: 2020 CERN
+
 *.o
 *.a
 *.so.*

lib/Makefile

+# SPDX-License-Identifier: LGPL-3.0-or-later
+#
+# Copyright (C) 2020 CERN
+
 # If it exists includes Makefile.specific. In this Makefile, you should put
 # specific Makefile code that you want to run before this. For example,
 # build a particular environment.

tools/.gitignore

+# SPDX-License-Identifier: CC0-1.0
+#
+# SPDX-FileCopyrightText: 2020 CERN
+
 lsfmc
 fmc-slot-eeprom
 compile_commands.json

tools/Makefile

+# SPDX-License-Identifier: LGPL-3.0-or-later
+#
+# Copyright (C) 2020 CERN
+
 # If it exists includes Makefile.specific. In this Makefile, you should put
 # specific Makefile code that you want to run before this. For example,
 # build a particular environment.