anchor.diff:  
     ycmd = callPackage ../development/tools/misc/ycmd {
       inherit (darwin.apple_sdk.frameworks) Cocoa;
  -    llvmPackages = llvmPackages_5;
       python = python2;
     };
   
  
positive.code:     inherit (stdenvAdapters) overrideCC;
    };
  
    llvmPackages_4 = callPackage ../development/compilers/llvm/4 ({
      inherit (stdenvAdapters) overrideCC;
    } // stdenv.lib.optionalAttrs stdenv.isDarwin {
      cmake = cmake.override { isBootstrap = true; };
      libxml2 = libxml2.override { pythonSupport = false; };
      python2 = callPackage ../development/interpreters/python/cpython/2.7/boot.nix { inherit (darwin) CF configd; };
    });
  
    llvmPackages_5 = callPackage ../development/compilers/llvm/5 {
      inherit (stdenvAdapters) overrideCC;
    };
  
    manticore = callPackage ../development/compilers/manticore { };
  
  
negative.code:     # makes it slower, but during runtime we link against just mesa_drivers
      # through /run/opengl-driver*, which is overriden according to config.grsecurity
      # grsecEnabled = true; # no more support in nixpkgs ATM
    });
  
    mesa_glu =  mesaDarwinOr (callPackage ../development/libraries/mesa-glu { });
  