anchor.diff:    buildInputs = [ ncurses ] ++ targetToolchains
       ++ optional (!forceBundledLLVM) llvmShared;
   
  -  # https://github.com/rust-lang/rust/issues/30181
  -  # enableParallelBuilding = false; # missing files during linking, occasionally
  -
     outputs = [ "out" "doc" ];
     setOutputFlags = false;
   
  +  # Disable codegen units for the tests.
     preCheck = ''
  +    export RUSTFLAGS=
       export TZDIR=${tzdata}/share/zoneinfo
     '' +
     # Ensure TMPDIR is set, and disable a test that removing the HOME
  
positive.code:   # This loosens the hard restrictions on bootstrapping-compiler
    # versions.
    RUSTC_BOOTSTRAP = "1";
  
    src = fetchgit {
      url = https://github.com/rust-lang/rust;
  
negative.code:     sed -i '28s/home_dir().is_some()/true/' ./src/test/run-pass/env-home-dir.rs
    '';
  
    doCheck = true;
    dontSetConfigureCross = true;
  
    enableParallelBuilding = true;
  
    meta = with stdenv.lib; {
      homepage = http://www.rust-lang.org/;
      description = "A safe, concurrent, practical language";
      maintainers = with maintainers; [ madjar cstrahan wizeman globin havvy wkennington retrry ];
      license = [ licenses.mit licenses.asl20 ];
      platforms = platforms.linux ++ platforms.darwin;
    };
  }
  