File headers: SPDX License migration

Use a shorter/simpler license convention, stops the header taking so
much space.

Follow the SPDX license specification: https://spdx.org/licenses

- C/C++/objc/objc++
- Python
- Shell Scripts
- CMake, GNUmakefile

While most of the source tree has been included

- `./extern/` was left out.
- `./intern/cycles` & `./intern/atomic` are also excluded because they
  use different header conventions.

doc/license/SPDX-license-identifiers.txt has been added to list SPDX all
used identifiers.

See P2788 for the script that automated these edits.

Reviewed By: brecht, mont29, sergey

Ref D14069

24 files changed, 48 insertions, 460 deletions

diff --git a/extern/CMakeLists.txt b/extern/CMakeLists.txt
index be76e8b0db1..35da67d05a4 100644
--- a/extern/CMakeLists.txt
+++ b/extern/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2006, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2006 Blender Foundation. All rights reserved.
 
 # Libs that adhere to strict flags
 add_subdirectory(curve_fit_nd)
diff --git a/extern/binreloc/CMakeLists.txt b/extern/binreloc/CMakeLists.txt
index 4dfe960c571..b89eac87303 100644
--- a/extern/binreloc/CMakeLists.txt
+++ b/extern/binreloc/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2008 by The Blender Foundation
-# All rights reserved.
-#
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2008 Blender Foundation. All rights reserved.
 
 set(INC
   include
diff --git a/extern/bullet2/CMakeLists.txt b/extern/bullet2/CMakeLists.txt
index 6138795f241..f8b3e8abbc8 100644
--- a/extern/bullet2/CMakeLists.txt
+++ b/extern/bullet2/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2006, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2006 Blender Foundation. All rights reserved.
 
 # avoid noisy warnings
 if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_C_COMPILER_ID MATCHES "Clang")
diff --git a/extern/ceres/CMakeLists.txt b/extern/ceres/CMakeLists.txt
index 51cf9657319..1d8a611b107 100644
--- a/extern/ceres/CMakeLists.txt
+++ b/extern/ceres/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2012, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2012 Blender Foundation. All rights reserved.
 
 # NOTE: This file is automatically generated by bundle.sh script
 #       If you're doing changes in this file, please update template
diff --git a/extern/clew/CMakeLists.txt b/extern/clew/CMakeLists.txt
index cffbf4e855f..297d9531853 100644
--- a/extern/clew/CMakeLists.txt
+++ b/extern/clew/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2006, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2006 Blender Foundation. All rights reserved.
 
 set(INC
   .
diff --git a/extern/cuew/CMakeLists.txt b/extern/cuew/CMakeLists.txt
index de54d9642ce..5ff31ec924f 100644
--- a/extern/cuew/CMakeLists.txt
+++ b/extern/cuew/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2006, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2006 Blender Foundation. All rights reserved.
 
 set(INC
   .
diff --git a/extern/curve_fit_nd/CMakeLists.txt b/extern/curve_fit_nd/CMakeLists.txt
index 11b16c8fa8a..401e1f40cac 100644
--- a/extern/curve_fit_nd/CMakeLists.txt
+++ b/extern/curve_fit_nd/CMakeLists.txt
@@ -1,20 +1,4 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
 
 set(INC
   .
diff --git a/extern/draco/CMakeLists.txt b/extern/draco/CMakeLists.txt
index d4cfeea4bee..09bc6efd29f 100644
--- a/extern/draco/CMakeLists.txt
+++ b/extern/draco/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2019, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2019 Blender Foundation. All rights reserved.
 
 # Build Draco library.
 add_subdirectory(draco)
diff --git a/extern/gflags/CMakeLists.txt b/extern/gflags/CMakeLists.txt
index 9179ad7fed0..82455c52e55 100644
--- a/extern/gflags/CMakeLists.txt
+++ b/extern/gflags/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2016, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2016 Blender Foundation. All rights reserved.
 
 set(INC
   src
diff --git a/extern/glew-es/CMakeLists.txt b/extern/glew-es/CMakeLists.txt
index deb73b30455..1e334f9995b 100644
--- a/extern/glew-es/CMakeLists.txt
+++ b/extern/glew-es/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2013, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2013 Blender Foundation. All rights reserved.
 
 set(INC
   include
diff --git a/extern/glew/CMakeLists.txt b/extern/glew/CMakeLists.txt
index 59f13eb73c7..bd35fa81538 100644
--- a/extern/glew/CMakeLists.txt
+++ b/extern/glew/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2006, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2006 Blender Foundation. All rights reserved.
 
 # avoid noisy warnings
 if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_C_COMPILER_ID MATCHES "Clang")
diff --git a/extern/glog/CMakeLists.txt b/extern/glog/CMakeLists.txt
index 2a9736425a8..f25c72d830e 100644
--- a/extern/glog/CMakeLists.txt
+++ b/extern/glog/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2016, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2016 Blender Foundation. All rights reserved.
 
 set(INC
   src
diff --git a/extern/gmock/CMakeLists.txt b/extern/gmock/CMakeLists.txt
index faa133265d3..2a2e21f515b 100644
--- a/extern/gmock/CMakeLists.txt
+++ b/extern/gmock/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2014, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2014 Blender Foundation. All rights reserved.
 
 set(INC
   .
diff --git a/extern/gtest/CMakeLists.txt b/extern/gtest/CMakeLists.txt
index 42a1cd6fbc7..363f951a1f0 100644
--- a/extern/gtest/CMakeLists.txt
+++ b/extern/gtest/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2014, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2014 Blender Foundation. All rights reserved.
 
 # avoid noisy warnings
 if(CMAKE_COMPILER_IS_GNUCC)
diff --git a/extern/hipew/CMakeLists.txt b/extern/hipew/CMakeLists.txt
index d215ea8c691..abcd74a3efb 100644
--- a/extern/hipew/CMakeLists.txt
+++ b/extern/hipew/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2021, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2021 Blender Foundation. All rights reserved.
 
 set(INC
   .
diff --git a/extern/lzma/CMakeLists.txt b/extern/lzma/CMakeLists.txt
index d76b418fd74..67b527d2217 100644
--- a/extern/lzma/CMakeLists.txt
+++ b/extern/lzma/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2006, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2006 Blender Foundation. All rights reserved.
 
 # avoid noisy warnings
 if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_C_COMPILER_ID MATCHES "Clang")
diff --git a/extern/lzo/CMakeLists.txt b/extern/lzo/CMakeLists.txt
index 630918dc92c..0cea8169d06 100644
--- a/extern/lzo/CMakeLists.txt
+++ b/extern/lzo/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2006, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2006 Blender Foundation. All rights reserved.
 
 remove_strict_flags()
 
diff --git a/extern/mantaflow/CMakeLists.txt b/extern/mantaflow/CMakeLists.txt
index 9b047eb1a3e..c9e2b54ef18 100644
--- a/extern/mantaflow/CMakeLists.txt
+++ b/extern/mantaflow/CMakeLists.txt
@@ -1,27 +1,7 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2016, Blender Foundation
-# All rights reserved.
-#
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2016 Blender Foundation. All rights reserved.
 # The Original Code is: all of this file.
-#
-# Contributor(s): Sebastian Barschkis (sebbas)
-#
-# ***** END GPL LICENSE BLOCK *****
+# Contributor(s): Sebastian Barschkis (sebbas).
 
 # Mantaflow triggers a clang-cl compiler error with versions before 9.0.1
 # Since mantaflow does not appear to be using OpenMP at this point in time,
diff --git a/extern/quadriflow/CMakeLists.txt b/extern/quadriflow/CMakeLists.txt
index 1ab2322f73b..bc4d624afa9 100644
--- a/extern/quadriflow/CMakeLists.txt
+++ b/extern/quadriflow/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2019, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2019 Blender Foundation. All rights reserved.
 
 # avoid noisy warnings
 if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_C_COMPILER_ID MATCHES "Clang")
diff --git a/extern/rangetree/CMakeLists.txt b/extern/rangetree/CMakeLists.txt
index b5c209d5aa3..559bedea2e5 100644
--- a/extern/rangetree/CMakeLists.txt
+++ b/extern/rangetree/CMakeLists.txt
@@ -1,20 +1,4 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
 
 set(INC
   .
diff --git a/extern/sdlew/CMakeLists.txt b/extern/sdlew/CMakeLists.txt
index 29bae5e4782..7f8300909a7 100644
--- a/extern/sdlew/CMakeLists.txt
+++ b/extern/sdlew/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2006, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2006 Blender Foundation. All rights reserved.
 
 set(INC
   .
diff --git a/extern/smaa_areatex/CMakeLists.txt b/extern/smaa_areatex/CMakeLists.txt
index 2386b0e7b79..cee7ddedef7 100644
--- a/extern/smaa_areatex/CMakeLists.txt
+++ b/extern/smaa_areatex/CMakeLists.txt
@@ -1,26 +1,6 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2017, Blender Foundation
-# All rights reserved.
-#
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2017 Blender Foundation. All rights reserved.
 # The Original Code is: all of this file.
-#
-# Contributor(s): IRIE Shinsuke
-#
-# ***** END GPL LICENSE BLOCK *****
+# Contributor(s): IRIE Shinsuke.
 
 add_executable(smaa_areatex smaa_areatex.cpp)
diff --git a/extern/wcwidth/CMakeLists.txt b/extern/wcwidth/CMakeLists.txt
index 805655de26a..126eeeb2006 100644
--- a/extern/wcwidth/CMakeLists.txt
+++ b/extern/wcwidth/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2013, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2013 Blender Foundation. All rights reserved.
 
 set(INC
   .
diff --git a/extern/xdnd/CMakeLists.txt b/extern/xdnd/CMakeLists.txt
index 3da6f728620..4f431257093 100644
--- a/extern/xdnd/CMakeLists.txt
+++ b/extern/xdnd/CMakeLists.txt
@@ -1,22 +1,5 @@
-# ***** BEGIN GPL LICENSE BLOCK *****
-#
-# This program 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 2
-# of the License, or (at your option) any later version.
-#
-# This program 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-#
-# The Original Code is Copyright (C) 2012, Blender Foundation
-# All rights reserved.
-# ***** END GPL LICENSE BLOCK *****
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2012 Blender Foundation. All rights reserved.
 
 set(INC
   .