[llvm-branch-commits] [clang] [llvm] [lit] Make builtin cat work with stdin (PR #158447)

[Paul Kirth via llvm-branch-commits]

https://github.com/ilovepi approved this pull request.

I slightly wonder if we should accept `-` too, but I doubt that would see much use in the tests. I figure we can cross that bridge if something needs it.

https://github.com/llvm/llvm-project/pull/158447