anchor.diff:  
     src = fetchgit {
       url = "https://gitlab.haskell.org/ghc/ghc.git/";
  -    rev = "5d651c78fed7e55b3b3cd21a04499d1a2f75204d";
  -    sha256 = "1z9xg8jsqr9id985wxfhkjyb3kpyrmr7vjdqzfv42cpxynd483r8";
  +    rev = "64923cf295ea914db458547432237a5ed1eff571";
  +    sha256 = "1s9sm4gf4r71lk0s7h9v217rxfwjf435q1jji90hlxz23wvmhr6d";
     };
   
     enableParallelBuilding = true;
  
positive.code:     ghc bootPkgs.alex bootPkgs.happy bootPkgs.hscolour
    ] ++ lib.optionals enableDocs [
      sphinx
    ] ++ lib.optionals stdenv.isDarwin [
      # TODO(@sternenseemann): use XATTR env var once we have
      # https://gitlab.haskell.org/ghc/ghc/-/merge_requests/6447
      xattr
    ];
  
    # For building runtime libs
  
negative.code:     export NIX_LDFLAGS+=" -rpath $out/lib/ghc-${version}"
    '' + lib.optionalString stdenv.isDarwin ''
      export NIX_LDFLAGS+=" -no_dtrace_dof"
  
      # GHC tries the host xattr /usr/bin/xattr by default which fails since it expects python to be 2.7
      export XATTR=${lib.getBin xattr}/bin/xattr
    '' + lib.optionalString targetPlatform.useAndroidPrebuilt ''
      sed -i -e '5i ,("armv7a-unknown-linux-androideabi", ("e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64", "cortex-a8", ""))' llvm-targets
    '' + lib.optionalString targetPlatform.isMusl ''
  