inkscape-with-extension: make enabling all extensions easier

Previously, we needed something like

inkscape-with-extensions.override { inkscapeExtensions = builtins.filter lib.isDerivation (builtins.attrValues inkscape-extensions); }

Now, we can just do

inkscape-with-extensions.override { inkscapeExtensions = null; }

pkgs/applications/graphics/inkscape/with-extensions.nix

···
 , inkscape
 , symlinkJoin
 , makeWrapper
-, inkscapeExtensions ? []
+, inkscapeExtensions ? [ ]
+, inkscape-extensions
 }:
 
+let
+  allExtensions = lib.filter (pkg: lib.isDerivation pkg && !pkg.meta.broken or false) (lib.attrValues inkscape-extensions);
+  selectedExtensions = if inkscapeExtensions == null then allExtensions else inkscapeExtensions;
+in
+
 symlinkJoin {
   name = "inkscape-with-extensions-${lib.getVersion inkscape}";
 
-  paths = [ inkscape ] ++ inkscapeExtensions;
+  paths = [ inkscape ] ++ selectedExtensions;
 
   nativeBuildInputs = [ makeWrapper ];