anchor.diff:    propagatedBuildInputs = [ "${toolchains}/XcodeDefault.xctoolchain" ];
   
     passthru = {
  -    inherit xcbuild;
  +    inherit xcbuild xcrun;
       toolchain = "${toolchains}/XcodeDefault.xctoolchain";
       sdk = "${sdks}/${sdkName}";
       platform = "${platforms}/${xcodePlatform}.platform";
  
positive.code: { stdenv, makeWrapper, writeText, runCommand
  , CoreServices, ImageIO, CoreGraphics
  , runtimeShell, callPackage
  , xcodePlatform ? stdenv.targetPlatform.xcodePlatform or "MacOSX"
  
negative.code: done
    '';
  
    xcrun = writeShellScriptBin "xcrun" ''
  while [ $# -gt 0 ]; do
     case "$1" in
           --sdk | -sdk) shift ;;
  