[compiler-rt] [compiler-rt] Expose shared DSO helpers for compiler-rt runtimes (PR #191098)

[Rainer Orth via llvm-commits]

rorth wrote:

This is anything but NFC: it broke both the [Solaris/sparcv9](https://lab.llvm.org/buildbot/#/builders/13/builds/12618) and [Solaris/amd64](https://lab.llvm.org/staging/#/builders/120/builds/17547) buildbots.  Please fix or revert!

https://github.com/llvm/llvm-project/pull/191098