[llvm-dev] clang+llvm-9.0.0-x86_64-linux-gnu-ubuntu-14.04 links against libc++ instead of libstdc++

[Fangrui Song via llvm-dev]

The Ubuntu 14.04 prebuilt binary on http://releases.llvm.org/download.html#9.0.0 seems to be built against libc++:

% nm -Cu libLLVMCore.a | sed -n '/ std::__1/{p;q}'
                 U std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::find(char, unsigned long) const

Is this expected? With a brief reading of
https://llvm.org/docs/ReleaseProcess.html, I guess the prebuilt binaries were likely built with llvm/utils/release/test-release.sh, but I cannot find any LLVM_ENABLE_LIBCXX setting in the script.