LLVM 9 Switches to a Less Free License

[grarpamp]

https://news.ycombinator.com/item?id=21018675

https://www.openbsd.org/policy.html
https://cvsweb.openbsd.org/src/share/misc/license.template?rev=HEAD
https://lists.llvm.org/pipermail/llvm-dev/2017-April/112300.html

https://github.com/llvm/llvm-project/blob/release/8.x/clang/LICENSE.TXT
https://github.com/llvm/llvm-project/blob/release/9.x/clang/LICENSE.TXT