Add a proper README to show how to build & run the lifetime checks

[WallStProg]

I've been building clang succesfully for a while from svn, but when I build this project I don't get e.g., clang in bin.

I see that the clang project redirects here, so I'm assuming that it is not needed.

TIA for any hints!

build.txt

[mgehre]

I think you are missing -DLLVM_ENABLE_PROJECTS=clang on cmake commandline. See
https://github.com/mgehre/llvm-project/blob/lifetime/.github/workflows/ccpp.yml for how we built in the CI.

[WallStProg]

Thanks! That did the trick, and I can see "-Wdangling-gsl" warnings in the output (thankfully just a few ;-)

Are there any specific compiler flags that should be used to generate addl. warnings, or is the default set also the most stringent?

Thanks again for the help -- really cool stuff!

[mgehre]

I appreciate it! I added more information to README.md. Let me know if you have more questions!