anchor.diff: -{ stdenv, makeWrapper, writeText, runCommand
  +{ stdenv, makeWrapper, writeText, writeShellScriptBin, runCommand
   , CoreServices, ImageIO, CoreGraphics
   , runtimeShell, callPackage
   , xcodePlatform ? stdenv.targetPlatform.xcodePlatform or "MacOSX"
  
positive.code: done
    '';
  
    xcrun = writeText "xcrun" ''
  #!${runtimeShell}
  while [ $# -gt 0 ]; do
     case "$1" in
           --sdk | -sdk) shift ;;
  
negative.code:     --subst-var-by DEVELOPER_DIR $out/Applications/Xcode.app/Contents/Developer
    chmod +x $out/bin/xcode-select
  
    cp ${xcrun}/bin/xcrun $out/bin/xcrun
  
    for bin in PlistBuddy actool builtin-copy builtin-copyPlist \
               builtin-copyStrings builtin-copyTiff \
  