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
This required using a fork of Embree, newer LLVM version, unreleased ISPC
version and sse2neon directly from Git. Hopefully over time all the required
changes end up in official releases. For now we deviate from other platforms.
Based on contributions by Apple and Stefan Werner.
Ref D9527, D8237, T78710
