[llvm] [BOLT] Resolve symlink for library lookup (PR #126386)

[YongKang Zhu via llvm-commits]

yozhu wrote:

> The code is fine, but I was wondering what scenario you hit where the library is symlinked and you need to perform the extra step to resovle.

I hit this in our internal build system where a symlink to `llvm-bolt` is created and invoked by the build. The original library lookup logic is to check the directory of `../lib/` from the directory where bolt tool is located, and this patch adds an additional lookup at the target directory that the symlink points to.

https://github.com/llvm/llvm-project/pull/126386