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

[Peng Huang via llvm-commits]

phuang wrote:

Hi @browneee , Unfortunately, the ohos sdk's header file doesn't have `get_current_dir_name()` function. Even if sdk is updated to include `get_current_dir_name()`, I think llvm still need to compiled with older ohos sdk. So I think it is better to guard `__dfsw_get_current_dir_name()` and `__dfso_get_current_dir_name()` with `#ifndef __OHOS__` in llvm source code. I updated this PR, please take a look. thanks

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