[clang] [libcxx] [llvm] Plumb LIBCXX_INSTALL_LIBRARY_PATH through to Clang (#109895) (PR #176772)

[Carlo Cabrera via cfe-commits]

carlocab wrote:

Thanks for looking at this!

> I couldn't work out how to add a new regression test to check this, as it doesn't seem the required CMake vars are visible in lit - please correct me if I'm wrong.

You may want to look at https://github.com/llvm/llvm-project/blob/8168577795e1e36f73ccba17f566343fb613a3da/clang/test/lit.site.cfg.py.in for an example of exposing CMake vars to lit.

https://github.com/llvm/llvm-project/pull/176772