[libcxx-commits] [libcxx] [libc++] Compose the test suite Lit site config from harness and installation substitutions (PR #209638)

[Louis Dionne via libcxx-commits]

ldionne wrote:

Giving a heads up to @llvm/libcxx-vendors since this may require small tweaks to downstream testing configurations. Specifically, the tweak would be to remove the inclusion of `cmake-bridge` from the site config, as we do in this patch:

```
lit_config.load_config(config, '@CMAKE_CURRENT_BINARY_DIR@/cmake-bridge.cfg')
```

https://github.com/llvm/llvm-project/pull/209638