anchor.diff:      PREFIX=''${out/#\/}
       substituteInPlace swift-corelibs-xctest/build_script.py \
         --replace usr "$PREFIX"
  -    substituteInPlace swiftpm/Utilities/bootstrap \
  -      --replace \"usr\" \"$PREFIX\" \
  -      --replace usr/lib "$PREFIX/lib"
     '';
   
     buildPhase = builder;
  
positive.code:     # For more inforation, see: https://github.com/apple/swift/pull/3594#issuecomment-234169759
      clang = fetch {
        repo = "swift-clang";
        sha256 = "1ap26425zhn2sdw3m9snyrqhi4phv2fgblyv9wp8xppjlnjkax9k";
      };
      llvm = fetch {
        repo = "swift-llvm";
  
negative.code:     };
      foundation = fetch {
        repo = "swift-corelibs-foundation";
        sha256 = "1wys4xh7f6c7yjf210x41n2krmyi2qj1wpxbv0p48d230va1azj1";
      };
      libdispatch = fetch {
        repo = "swift-corelibs-libdispatch";
        sha256 = "0chnb0d4xjyn9wnc8bgimd5ji5igfyq891flgnqpfwr4y26496c1";
        fetchSubmodules = true;
      };
      swift = fetch {
        repo = "swift";
        sha256 = "0fsq1y8dz4ssn90akvzj36cqyblalb09bjzy4ikqn67mb5x99wpb";
      };
    };
  
  