anchor.diff:  
       # Add mandb locations for the above
       echo "MANDB_MAP	/nix/var/nix/profiles/default/share/man	/var/cache/man/nixpkgs" >> src/man_db.conf.in
  -
  -    # use absolute paths to reference programs, otherwise artifacts will have undeclared dependencies
  -    for f in configure.ac m4/man-check-progs.m4 m4/man-po4a.m4; do
  -      substituteInPlace $f \
  -        --replace AC_CHECK_PROGS AC_PATH_PROGS
  -    done
     '';
   
     configureFlags = [
  
positive.code:     # (multi-call binary). `apropos` is actually just a symlink to whatis. So we need to
      # make sure that we don't wrap symlinks (since that changes argv[0] to the -wrapped name)
      find "$out/bin" -type f | while read file; do
        wrapProgram "$file" --prefix PATH : "${groff}/bin"
      done
    '';
  
    postFixup = lib.optionalString (buildPackages.groff != groff) ''
      # Check to make sure none of the outputs depend on build-time-only groff:
      for outName in $outputs; do
        out=''${!outName}
        echo "Checking $outName(=$out) for references to build-time groff..."
        if grep -r '${buildPackages.groff}' $out; then
          echo "Found an erroneous dependency on groff ^^^" >&2
          exit 1
        fi
      done
    '';
  
    enableParallelBuilding = true;
  
  
negative.code:   outputs = [ "out" "doc" ];
    outputMan = "out"; # users will want `man man` to work
  
    strictDeps = true;
    nativeBuildInputs = [ autoreconfHook groff makeWrapper pkg-config zstd ];
    buildInputs = [ libpipeline db groff ]; # (Yes, 'groff' is both native and build input)
    checkInputs = [ libiconv /* for 'iconv' binary */ ];
  