anchor.diff:          [[ -e "$underlying" ]] || continue
           wrap ${targetPrefix}$variant ${./ld-wrapper.sh} $underlying
         done
  -
  -      set +u
       '';
   
     emulation = let
  
positive.code:     ''
  
      + ''
        set +u
        substituteAll ${./add-flags.sh} $out/nix-support/add-flags.sh
        substituteAll ${./add-hardening.sh} $out/nix-support/add-hardening.sh
        substituteAll ${../wrapper-common/utils.bash} $out/nix-support/utils.bash
  
negative.code: 
    installPhase =
      ''
        mkdir -p $out/bin $out/nix-support
  
        wrap() {
          local dst="$1"
          local wrapper="$2"
          export prog="$3"
          substituteAll "$wrapper" "$out/bin/$dst"
          chmod +x "$out/bin/$dst"
        }
      ''
  