anchor.diff:    inherit (stdenv.lib) optional optionalString;
     inherit (darwin.apple_sdk.frameworks) Security;
   
  -  llvmPackages = llvmPackages_7;
  -
  -  llvmSharedForBuild = pkgsBuildBuild.llvmPackages.llvm.override { enableSharedLibraries = true; };
  -  llvmSharedForHost = pkgsBuildHost.llvmPackages.llvm.override { enableSharedLibraries = true; };
  -  llvmSharedForTarget = pkgsBuildTarget.llvmPackages.llvm.override { enableSharedLibraries = true; };
  +  llvmSharedForBuild = pkgsBuildBuild.llvm_7.override { enableSharedLibraries = true; };
  +  llvmSharedForHost = pkgsBuildHost.llvm_7.override { enableSharedLibraries = true; };
  +  llvmSharedForTarget = pkgsBuildTarget.llvm_7.override { enableSharedLibraries = true; };
   
     # For use at runtime
  -  llvmShared = llvmPackages.llvm.override { enableSharedLibraries = true; };
  -in
  -
  -stdenv.mkDerivation rec {
  +  llvmShared = llvm_7.override { enableSharedLibraries = true; };
  +in stdenv.mkDerivation rec {
     pname = "rustc";
     version = "1.37.0";
   
  
positive.code:     url = "https://static.rust-lang.org/dist/rustc-${version}-src.tar.gz";
      sha256 = "1hrqprybhkhs6d9b5pjskfnc5z9v2l2gync7nb39qjb5s0h703hj";
    };
  
    # Provide the compiler-rt sources needed for profiling.
    preConfigure = ''
      mkdir src/llvm-project/compiler-rt
      tar xf ${llvmPackages.compiler-rt.src} -C src/llvm-project/compiler-rt --strip-components=1
    '';
  
    __darwinAllowLocalNetworking = true;
  
  
negative.code: { stdenv, removeReferencesTo, pkgsBuildBuild, pkgsBuildHost, pkgsBuildTarget
  , fetchurl, file, python2, tzdata, ps
  , llvm_7, darwin, git, cmake, rustPlatform
  , which, libffi, gdb
  , withBundledLLVM ? false
  }:
  