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

6 files changed, 6 insertions, 6 deletions

diff --git a/tests/performance/api/__init__.py b/tests/performance/api/__init__.py
index 2dc9283c44a..2bd7b98d406 100644
--- a/tests/performance/api/__init__.py
+++ b/tests/performance/api/__init__.py
@@ -1,4 +1,4 @@
-# Apache License, Version 2.0
+# SPDX-License-Identifier: Apache-2.0
 
 from .environment import TestEnvironment
 from .device import TestDevice, TestMachine
diff --git a/tests/performance/api/config.py b/tests/performance/api/config.py
index 5e7ee380068..03d699cfdfb 100644
--- a/tests/performance/api/config.py
+++ b/tests/performance/api/config.py
@@ -1,4 +1,4 @@
-# Apache License, Version 2.0
+# SPDX-License-Identifier: Apache-2.0
 
 import fnmatch
 import json
diff --git a/tests/performance/api/device.py b/tests/performance/api/device.py
index 1e930a12352..fb11c5948e6 100644
--- a/tests/performance/api/device.py
+++ b/tests/performance/api/device.py
@@ -1,4 +1,4 @@
-# Apache License, Version 2.0
+# SPDX-License-Identifier: Apache-2.0
 
 import platform
 import subprocess
diff --git a/tests/performance/api/environment.py b/tests/performance/api/environment.py
index 4db81524120..61a7c5dff7b 100644
--- a/tests/performance/api/environment.py
+++ b/tests/performance/api/environment.py
@@ -1,4 +1,4 @@
-# Apache License, Version 2.0
+# SPDX-License-Identifier: Apache-2.0
 
 import base64
 import glob
diff --git a/tests/performance/api/graph.py b/tests/performance/api/graph.py
index 721b04d1f43..6c9ba70141f 100644
--- a/tests/performance/api/graph.py
+++ b/tests/performance/api/graph.py
@@ -1,4 +1,4 @@
-# Apache License, Version 2.0
+# SPDX-License-Identifier: Apache-2.0
 
 from . import TestQueue
 
diff --git a/tests/performance/api/test.py b/tests/performance/api/test.py
index 7e8193d2c21..72e72463cd1 100644
--- a/tests/performance/api/test.py
+++ b/tests/performance/api/test.py
@@ -1,4 +1,4 @@
-# Apache License, Version 2.0
+# SPDX-License-Identifier: Apache-2.0
 
 import abc
 import fnmatch