[libcxx-dev] Problem installing libcxx and libcxxabi using Bootstrapping on Amazon Linux 2

[Raul Tambre via libcxx-dev]

 > Tried creating a symlink, but unfortunately getting the same error.

Then it sounds like /usr/local/lib/x86_64-unknown-linux still isn't on ld's 
search path. Run the faulty linker command -v, which should print a bunch of 
info including the search paths.

 > (after doing "ninja-build -C build install-runtimes") ??

install-runtimes only installs the runtimes (libc++, libc++abi and libunwind in 
your case). Use the regular install target for the rest.