anchor.diff:          then ''-DNIXPKGS_LIBDBUS="${dbus.lib}/lib/libdbus-1"''
           else ''-DNIXPKGS_LIBDBUS=""'')
       ]
  +
       ++ lib.optional mesaSupported
          ''-DNIXPKGS_MESA_GL="${mesa.out}/lib/libGL"''
  +
       ++ lib.optionals stdenv.isDarwin
       [
         "-D__MAC_OS_X_VERSION_MAX_ALLOWED=1090"
  
positive.code:     ++ lib.optional (mysql != null) mysql.lib
      ++ lib.optional (postgresql != null) postgresql;
  
    nativeBuildInputs = [ bison flex gperf lndir perl pkgconfig python2 ] ++ lib.optional (!stdenv.isDarwin) patchelf;
  
    # freetype-2.5.4 changed signedness of some struct fields
    NIX_CFLAGS_COMPILE =
  
negative.code:           popd
        fi
      ''
  
      # fixup .pc file (where to find 'moc' etc.)
      + lib.optionalString (!stdenv.isDarwin) ''
        sed -i "$dev/lib/pkgconfig/Qt5Core.pc" \
            -e "/^host_bins=/ c host_bins=$dev/bin"
      ''
  
      # Don' move .prl files on darwin because they end up in
      # "dev/lib/Foo.framework/Foo.prl" which interferes with subsequent
      # use of lndir in the qtbase setup-hook. On Linux, the .prl files
  