anchor.diff:    # 10.9. This is a temporary measure until nixpkgs darwin support is
     # updated.
     postPatch = stdenv.lib.optionalString stdenv.isDarwin ''
  -        sed -i 's/os_trace(\(.*\)");$/printf(\1\\n");/g' ./projects/compiler-rt/lib/sanitizer_common/sanitizer_mac.cc
  +    sed -i 's/os_trace(\(.*\)");$/printf(\1\\n");/g' ./projects/compiler-rt/lib/sanitizer_common/sanitizer_mac.cc
     ''
     # Patch llvm-config to return correct library path based on --link-{shared,static}.
     + stdenv.lib.optionalString (enableSharedLibraries) ''
       substitute '${./llvm-outputs.patch}' ./llvm-outputs.patch --subst-var lib
       patch -p1 < ./llvm-outputs.patch
  +  ''
  +  # Remove broken tests: (https://bugs.llvm.org//show_bug.cgi?id=31610)
  +  + ''
  +    rm test/CodeGen/AMDGPU/invalid-opencl-version-metadata1.ll
  +    rm test/CodeGen/AMDGPU/invalid-opencl-version-metadata2.ll
  +    rm test/CodeGen/AMDGPU/invalid-opencl-version-metadata3.ll
  +    rm test/CodeGen/AMDGPU/runtime-metadata.ll
     '';
   
     # hacky fix: created binaries need to be run before installation
  
positive.code:     ln -s $lib/lib/libLLVM.dylib $lib/lib/libLLVM-${release_version}.dylib
    '';
  
    enableParallelBuilding = true;
  
    passthru.src = src;
  
negative.code:     rm -fR $out
  
      paxmark m bin/{lli,llvm-rtdyld}
      paxmark m unittests/ExecutionEngine/MCJIT/MCJITTests
      paxmark m unittests/ExecutionEngine/Orc/OrcJITTests
      paxmark m unittests/Support/SupportTests
      paxmark m bin/lli-child-target
    '';
  
    preCheck = ''
      export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$PWD/lib
    '';
  
    postInstall = ""
  