build: use SPDX license tags

The license folder is a core part of OpenWrt and all GPL-2.0 licensed.
Use SPDX license tags to allow machines to check licenses.

Signed-off-by: Paul Spooren <mail@aparcar.org>
[rebase, keep some Copyright lines, sharpen commit message]
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

30 files changed, 57 insertions, 142 deletions

diff --git a/include/autotools.mk b/include/autotools.mk
index ae320fbde0f..ec67c844f7e 100644
--- a/include/autotools.mk
+++ b/include/autotools.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2007-2012 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2007-2020 OpenWrt.org
 
 autoconf_bool = $(patsubst %,$(if $($(1)),--enable,--disable)-%,$(2))
 
diff --git a/include/debug.mk b/include/debug.mk
index 59a99c0f77d..98a1d6e889b 100644
--- a/include/debug.mk
+++ b/include/debug.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2007 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2007-2020 OpenWrt.org
 
 # debug flags:
 #
diff --git a/include/depends.mk b/include/depends.mk
index ace7139000d..0080b97876f 100644
--- a/include/depends.mk
+++ b/include/depends.mk
@@ -1,9 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2007 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2007-2020 OpenWrt.org
+
 # define a dependency on a subtree
 # parameters:
 #	1: directories/files
diff --git a/include/download.mk b/include/download.mk
index d393bf39071..a638e69382c 100644
--- a/include/download.mk
+++ b/include/download.mk
@@ -1,10 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Copyright (C) 2006-2012 OpenWrt.org
 # Copyright (C) 2016 LEDE project
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
 
 PROJECT_GIT = https://git.openwrt.org
 
diff --git a/include/feeds.mk b/include/feeds.mk
index 2b259b96b3e..ef5fef7f4ba 100644
--- a/include/feeds.mk
+++ b/include/feeds.mk
@@ -1,10 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Copyright (C) 2014 OpenWrt.org
 # Copyright (C) 2016 LEDE Project
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
 
 -include $(TMP_DIR)/.packageauxvars
 
diff --git a/include/hardening.mk b/include/hardening.mk
index 4e49e6b1b90..6acd862f5c4 100644
--- a/include/hardening.mk
+++ b/include/hardening.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2015 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2015-2020 OpenWrt.org
 
 PKG_CHECK_FORMAT_SECURITY ?= 1
 PKG_ASLR_PIE ?= 1
diff --git a/include/host-build.mk b/include/host-build.mk
index ab6e05e14f5..e4a5c48e72f 100644
--- a/include/host-build.mk
+++ b/include/host-build.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2006-2010 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2006-2020 OpenWrt.org
 
 include $(INCLUDE_DIR)/download.mk
 
diff --git a/include/image.mk b/include/image.mk
index 6843b935f72..25301082118 100644
--- a/include/image.mk
+++ b/include/image.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2006-2010 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2006-2020 OpenWrt.org
 
 override TARGET_BUILD=
 include $(INCLUDE_DIR)/prereq.mk
diff --git a/include/kernel-build.mk b/include/kernel-build.mk
index 6123c9d4567..66a9f64c802 100644
--- a/include/kernel-build.mk
+++ b/include/kernel-build.mk
@@ -1,9 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2006-2007 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2006-2020 OpenWrt.org
+
 include $(INCLUDE_DIR)/prereq.mk
 include $(INCLUDE_DIR)/depends.mk
 
diff --git a/include/kernel-defaults.mk b/include/kernel-defaults.mk
index 5b376dc9da9..e5a0ba367bf 100644
--- a/include/kernel-defaults.mk
+++ b/include/kernel-defaults.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2006-2015 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2006-2020 OpenWrt.org
 
 ifdef CONFIG_STRIP_KERNEL_EXPORTS
   KERNEL_MAKEOPTS += \
diff --git a/include/kernel-version.mk b/include/kernel-version.mk
index e5243089641..5861b03670c 100644
--- a/include/kernel-version.mk
+++ b/include/kernel-version.mk
@@ -1,5 +1,5 @@
-# Use the default kernel version if the Makefile doesn't override it
 
+# Use the default kernel version if the Makefile doesn't override it
 LINUX_RELEASE?=1
 
 ifdef CONFIG_TESTING_KERNEL
diff --git a/include/kernel.mk b/include/kernel.mk
index 1466048b0c1..d2a5b421384 100644
--- a/include/kernel.mk
+++ b/include/kernel.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2006-2015 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2006-2020 OpenWrt.org
 
 ifneq ($(filter check,$(MAKECMDGOALS)),)
 CHECK:=1
diff --git a/include/netfilter.mk b/include/netfilter.mk
index 889beb7a983..60f031e9a71 100644
--- a/include/netfilter.mk
+++ b/include/netfilter.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2006-2014 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2006-2020 OpenWrt.org
 
 ifneq ($(__inc_netfilter),1)
 __inc_netfilter:=1
diff --git a/include/nls.mk b/include/nls.mk
index 04838821b4f..742f8c25aa6 100644
--- a/include/nls.mk
+++ b/include/nls.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2011-2012 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2011-2020 OpenWrt.org
 
 # iconv full
 ifeq ($(CONFIG_BUILD_NLS),y)
diff --git a/include/package-bin.mk b/include/package-bin.mk
index 4ae049af540..192f0726d20 100644
--- a/include/package-bin.mk
+++ b/include/package-bin.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2007-2014 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2007-2020 OpenWrt.org
 
 ifeq ($(DUMP),)
   define BuildTarget/bin
diff --git a/include/package-defaults.mk b/include/package-defaults.mk
index 2a04bc17e90..3ee3a965f20 100644
--- a/include/package-defaults.mk
+++ b/include/package-defaults.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2006 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2006-2020 OpenWrt.org
 
 PKG_DEFAULT_DEPENDS = +libc +USE_GLIBC:librt +USE_GLIBC:libpthread
 
diff --git a/include/package-dumpinfo.mk b/include/package-dumpinfo.mk
index ef98c482fbd..30b0187f119 100644
--- a/include/package-dumpinfo.mk
+++ b/include/package-dumpinfo.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2006 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2006-2020 OpenWrt.org
 
 ifneq ($(DUMP),)
 
diff --git a/include/package-ipkg.mk b/include/package-ipkg.mk
index 32de3cc93ee..ead4b5742cb 100644
--- a/include/package-ipkg.mk
+++ b/include/package-ipkg.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2006-2014 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2006-2020 OpenWrt.org
 
 ifndef DUMP
   include $(INCLUDE_DIR)/feeds.mk
diff --git a/include/package-seccomp.mk b/include/package-seccomp.mk
index fa49617d41a..86e834450d5 100644
--- a/include/package-seccomp.mk
+++ b/include/package-seccomp.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2015 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2015-2020 OpenWrt.org
 
 PKG_CONFIG_DEPENDS+= CONFIG_KERNEL_SECCOMP
 
diff --git a/include/package.mk b/include/package.mk
index 24128c53a66..dc1f69a710e 100644
--- a/include/package.mk
+++ b/include/package.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2006-2008 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2006-2020 OpenWrt.org
 
 __package_mk:=1
 
diff --git a/include/prereq-build.mk b/include/prereq-build.mk
index fb11a070a13..6dce11cba26 100644
--- a/include/prereq-build.mk
+++ b/include/prereq-build.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2006-2012 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2006-2020 OpenWrt.org
 
 include $(TOPDIR)/rules.mk
 include $(INCLUDE_DIR)/prereq.mk
diff --git a/include/prereq.mk b/include/prereq.mk
index 6d14140792f..c11178a884b 100644
--- a/include/prereq.mk
+++ b/include/prereq.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2006-2015 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2006-2020 OpenWrt.org
 
 ifneq ($(__prereq_inc),1)
 __prereq_inc:=1
diff --git a/include/quilt.mk b/include/quilt.mk
index 56f674a2f39..00597ca0f2a 100644
--- a/include/quilt.mk
+++ b/include/quilt.mk
@@ -1,8 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2007-2009 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
+# Copyright (C) 2007-2020 OpenWrt.org
 
 ifeq ($(TARGET_BUILD),1)
   PKG_BUILD_DIR:=$(LINUX_DIR)
diff --git a/include/subdir.mk b/include/subdir.mk
index f01cd55f30b..be080859b79 100644
--- a/include/subdir.mk
+++ b/include/subdir.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2007 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2007-2020 OpenWrt.org
 
 ifeq ($(MAKECMDGOALS),prereq)
   SUBTARGETS:=prereq
diff --git a/include/target.mk b/include/target.mk
index edc6a146de0..7526224972e 100644
--- a/include/target.mk
+++ b/include/target.mk
@@ -1,10 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Copyright (C) 2007-2008 OpenWrt.org
 # Copyright (C) 2016 LEDE Project
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
 
 ifneq ($(__target_inc),1)
 __target_inc=1
diff --git a/include/toolchain-build.mk b/include/toolchain-build.mk
index 35d8c9380ec..b7a253b71b8 100644
--- a/include/toolchain-build.mk
+++ b/include/toolchain-build.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2009 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2009-2020 OpenWrt.org
 
 override CONFIG_AUTOREBUILD=
 override CONFIG_AUTOREMOVE=
diff --git a/include/toplevel.mk b/include/toplevel.mk
index 23bae149d46..744695b19c9 100644
--- a/include/toplevel.mk
+++ b/include/toplevel.mk
@@ -1,10 +1,6 @@
-# Makefile for OpenWrt
-#
-# Copyright (C) 2007-2012 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
+# SPDX-License-Identifier: GPL-2.0-only
 #
+# Copyright (C) 2007-2020 OpenWrt.org
 
 PREP_MK= OPENWRT_BUILD= QUIET=0
 
diff --git a/include/unpack.mk b/include/unpack.mk
index 5bb27d41c9a..6a56b8e742f 100644
--- a/include/unpack.mk
+++ b/include/unpack.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2006-2007 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2006-2020 OpenWrt.org
 
 HOST_TAR:=$(TAR)
 TAR_CMD=$(HOST_TAR) -C $(1)/.. $(TAR_OPTIONS)
diff --git a/include/verbose.mk b/include/verbose.mk
index d2600801954..3ecf842d118 100644
--- a/include/verbose.mk
+++ b/include/verbose.mk
@@ -1,9 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# Copyright (C) 2006 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
+# Copyright (C) 2006-2020 OpenWrt.org
 
 ifndef OPENWRT_VERBOSE
   OPENWRT_VERBOSE:=
diff --git a/include/version.mk b/include/version.mk
index b7f42e13bb1..f39e35cd099 100644
--- a/include/version.mk
+++ b/include/version.mk
@@ -1,10 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Copyright (C) 2012-2015 OpenWrt.org
 # Copyright (C) 2016 LEDE Project
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
 
 # Substituted by SDK, do not remove
 # REVISION:=x