nixpkgs/pkgs/applications/graphics/sane/config.nix

{ stdenv }:

{ paths }:

with stdenv.lib;
let installSanePath = path: ''
      if test -e "${path}/lib/sane"; then
        find "${path}/lib/sane" -not -type d -maxdepth 1 | while read backend; do
          ln -s $backend $out/lib/sane/$(basename $backend)
        done
      fi

      if test -e "${path}/etc/sane.d"; then
        find "${path}/etc/sane.d" -not -type d -maxdepth 1 | while read conf; do
          if test $(basename $conf) = "dll.conf"; then
            cat $conf >> $out/etc/sane.d/dll.conf
          else
            ln -s $conf $out/etc/sane.d/$(basename $conf)
          fi
        done
      fi

      if test -e "${path}/etc/sane.d/dll.d"; then
        find "${path}/etc/sane.d/dll.d" -not -type d -maxdepth 1 | while read conf; do
          ln -s $conf $out/etc/sane.d/dll.d/$(basename $conf)
        done
      fi
    '';
in
stdenv.mkDerivation {
  name = "sane-config";
  phases = "installPhase";

  installPhase = ''
    mkdir -p $out/etc/sane.d $out/etc/sane.d/dll.d $out/lib/sane
  '' + concatMapStrings installSanePath paths;
}