anchor.diff:                  })
                   else stdenv;
   
  +  # Compile the wasm32 sysroot to build the RLBox Sandbox
  +  # https://hacks.mozilla.org/2021/12/webassembly-and-back-again-fine-grained-sandboxing-in-firefox-95/
  +  # We only link c++ libs here, our compiler wrapper can find wasi libc and crt itself.
  +  wasiSysRoot = runCommand "wasi-sysroot" {} ''
  +    mkdir -p $out/lib/wasm32-wasi
  +    for lib in ${pkgsCross.wasi32.llvmPackages.libcxx}/lib/* ${pkgsCross.wasi32.llvmPackages.libcxxabi}/lib/*; do
  +      ln -s $lib $out/lib/wasm32-wasi
  +    done
  +  '';
   in
   
   buildStdenv.mkDerivation ({
  
positive.code:   ++ lib.optional ltoSupport "--enable-lto=cross" # Cross-language LTO.
    ++ lib.optional (ltoSupport && (buildStdenv.isAarch32 || buildStdenv.isi686 || buildStdenv.isx86_64)) "--disable-elf-hack"
    ++ lib.optional (ltoSupport && !buildStdenv.isDarwin) "--enable-linker=lld"
  
    ++ flag alsaSupport "alsa"
    ++ flag pulseaudioSupport "pulseaudio"
  
negative.code:   ++ lib.optionals enableDebugSymbols [ "--disable-strip" "--disable-install-strip" ]
  
    ++ lib.optional enableOfficialBranding "--enable-official-branding"
    ++ extraConfigureFlags;
  
    postConfigure = ''
  