Can't build clang the way I need without getting errors about scudo_standalone

I am trying to build clang 16.0.5 for x86_64 Ubuntu 20.04 so that I can build ARM64 executables with Asan. I’ve tried dozens of variants of cmake options and still get complaints when compiling about scudo_standalone not existing. Cannot find much of anything from googling and using Bing chat. What am I doing wrong? Current cmake command, which I wouldn’t be surprised has things I don’t really need it this:

cmake \
    -B build \
    -G "Ninja" \
    -DCMAKE_BUILD_TYPE=Release \
    llvm/ \
    -DLLVM_ENABLE_PROJECTS='clang;clang-tools-extra;lld' \
    -DLLVM_ENABLE_RUNTIMES='compiler-rt' \
    -DCOMPILER_RT_SANITIZERS_TO_BUILD='asan;dfsan;msan;tsan;cfi' \
    -DLLVM_RUNTIME_TARGETS='x86_64-pc-linux-gnu;aarch64-unknown-linux-gnu' \
    -DCLANG_DEFAULT_RTLIB=compiler-rt \