anchor.diff:        pysisyphus = super.python3.pkgs.toPythonApplication self.python3.pkgs.pysisyphus;
   
         qdng = callPackage ./pkgs/apps/qdng {
  +        stdenv = aggressiveStdenv;
           protobuf=super.protobuf3_11;
         };
   
  
positive.code:     # Add additional compiler flags
      extraAttrs = {
        mkDerivation = args: stdenv.mkDerivation ( args // {
          NIX_CFLAGS_COMPILE = toString (args.NIX_CFLAGS_COMPILE or "") + " -march=${arch} -mtune=${arch}";
        });
      };
    });
  
    optStdenv = makeOptStdenv final.stdenv cfg.optArch;
  
  
  
    #
  
negative.code:   lib = prev.lib;
  
    # Create a stdenv with CPU optimizations
    makeOptStdenv = stdenv: arch: extraCflags: if arch == null then stdenv else
    stdenv.override (old: {
      name = old.name + "-${arch}";
  
  