anchor.diff:  { lib
   , stdenv
   , fetchFromGitLab
  -, docbook-xsl-nons
   , gi-docgen
  -, gtk-doc
  -, libxml2
   , meson
   , ninja
   , pkg-config
  
positive.code:   };
  
    nativeBuildInputs = [
      docbook-xsl-nons
      gi-docgen
      gtk-doc
      libxml2 # for xmllint
      meson
      ninja
      pkg-config
  
negative.code:     runHook postCheck
    '';
  
    postFixup = ''
      # Cannot be in postInstall, otherwise _multioutDocs hook in preFixup will move right back.
      moveToOutput "share/doc" "$devdoc"
    '';
  
    passthru = {
  