paperless-ngx: change symlink to work with compressDrvWeb

Before compressDrvWeb would follow the frontend symlink into the nix
store and couldn't write it's file into the directories below the
symlink. lndir creates all dirs and then symlinks the actual files into
them which allows compressDrvWeb to place the compressed variants next
to them.

pkgs/applications/office/paperless-ngx/default.nix

@@ -21,6 +21,7 @@
 , pango
 , pkg-config
 , nltk-data
+, xorg
 }:
 
 let
@@ -121,6 +122,7 @@ python.pkgs.buildPythonApplication rec {
 
   nativeBuildInputs = [
     gettext
+    xorg.lndir
   ];
 
   propagatedBuildInputs = with python.pkgs; [
@@ -194,9 +196,9 @@ python.pkgs.buildPythonApplication rec {
   in ''
     runHook preInstall
 
-    mkdir -p $out/lib/paperless-ngx
+    mkdir -p $out/lib/paperless-ngx/static/frontend
     cp -r {src,static,LICENSE,gunicorn.conf.py} $out/lib/paperless-ngx
-    ln -s ${frontend}/lib/paperless-ui/frontend $out/lib/paperless-ngx/static/
+    lndir -silent ${frontend}/lib/paperless-ui/frontend $out/lib/paperless-ngx/static/frontend
     chmod +x $out/lib/paperless-ngx/src/manage.py
     makeWrapper $out/lib/paperless-ngx/src/manage.py $out/bin/paperless-ngx \
       --prefix PYTHONPATH : "${pythonPath}" \