[compiler-rt] Fix compile error on ohos (PR #118193)

[Andrew Browne via llvm-commits]

browneee wrote:

> Another solution, I can test `get_current_dir_name()` in cmake script, and guard it with HAS_GET_CURRENT_DIR_NAME macro. what do you think?

This would address this issue:

> * If you do this `#ifdef`, then later fix the OHOS sdk (add the missing function), people may hit issues where they have a version of llvm sources which `#ifdef` the function out, even though it is now present in OHOS.

But it would slightly increase this issue:

> This #ifdef is polluting the sanitizer code with a tiny bit of extra complexity for a bug (afaict) in a relatively uncommon platform.

I would still recommend fixing openharmony os's sdk by adding the missing function.

> They told me this function is not exposed in ohos sdk, but they didn't explain why. I will ask them to explain it.

Thanks! It would be good to at least hear why, before proceeding with workarounds.

https://github.com/llvm/llvm-project/pull/118193