[llvm-branch-commits] [compiler-rt] Allow running tests without installing first (PR #83088)

[Fangrui Song via llvm-branch-commits]

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

I have a regular clang build at /tmp/Rel. If I create a standalone compiler-rt build at /tmp/out/crt, I see that with this PR, clang invoked by llvm-lit will get `-resource-dir=/tmp/out/crt -Wl,-rpath,/tmp/out/crt/lib/linux`, which utilizes `include/sanitizer/*_interface.h` (used by certain asan tests) and runtime libraries.

```
#include <sanitizer/allocator_interface.h>
#include "sanitizer/asan_interface.h"
```

https://github.com/llvm/llvm-project/pull/83088