anchor.diff:    useLLVM = stdenv.hostPlatform.useLLVM or false;
     bareMetal = stdenv.hostPlatform.parsed.kernel.name == "none";
     haveLibc = stdenv.cc.libc != null;
  -  inherit (stdenv.hostPlatform) isMusl;
  +  inherit (stdenv.hostPlatform) isMusl isAarch64;
   
   in
   
  
positive.code:     "-DCOMPILER_RT_DEFAULT_TARGET_ONLY=ON"
      "-DCMAKE_C_COMPILER_TARGET=${stdenv.hostPlatform.config}"
      "-DCMAKE_ASM_COMPILER_TARGET=${stdenv.hostPlatform.config}"
    ] ++ lib.optionals (useLLVM || bareMetal || isMusl) [
      "-DCOMPILER_RT_BUILD_SANITIZERS=OFF"
      "-DCOMPILER_RT_BUILD_XRAY=OFF"
      "-DCOMPILER_RT_BUILD_LIBFUZZER=OFF"
      "-DCOMPILER_RT_BUILD_PROFILE=OFF"
    ] ++ lib.optionals ((useLLVM || bareMetal) && !haveLibc) [
      "-DCMAKE_C_COMPILER_WORKS=ON"
  
negative.code:     # "All of the code in the compiler-rt project is dual licensed under the MIT
      # license and the UIUC License (a BSD-like license)":
      license = with lib.licenses; [ mit ncsa ];
    };
  }
  