simplify overlay.nix

Move pkg definitions to pkgs/default.nix.
This allows us to just import the pkgs in overlay.nix and get rid of
the filtering to exclude the modules.

default.nix

@@ -1,16 +1,5 @@
 { pkgs ? import <nixpkgs> {} }:
-{
-  # 'lib', 'modules' and 'overlays' are special, see
-  # https://github.com/nix-community/NUR for more.
-  modules = import ./modules; # NixOS modules
 
-  nodeinfo = pkgs.callPackage ./pkgs/nodeinfo { };
+(import ./pkgs { inherit pkgs; }) // {
-  lightning-charge = pkgs.callPackage ./pkgs/lightning-charge { };
+  modules = import ./modules;
-  nanopos = pkgs.callPackage ./pkgs/nanopos { };
-  spark-wallet = pkgs.callPackage ./pkgs/spark-wallet { };
-  electrs = (pkgs.callPackage ./pkgs/electrs { }).rootCrate.build;
-  elementsd = pkgs.callPackage ./pkgs/elementsd { withGui = false; };
-  hwi = pkgs.callPackage ./pkgs/hwi { };
-  pylightning = pkgs.python3Packages.callPackage ./pkgs/pylightning { };
-  liquid-swap = pkgs.python3Packages.callPackage ./pkgs/liquid-swap { };
 }

overlay.nix

@@ -1,21 +1 @@
-# You can use this file as a nixpkgs overlay.
+self: super: import ./pkgs { pkgs = super; }
-# It's useful in the case where you don't want to add the whole NUR namespace
-# to your configuration.
-
-self: super:
-
-let filterSet =
-      (f: g: s: builtins.listToAttrs
-        (map
-          (n: { name = n; value = builtins.getAttr n s; })
-          (builtins.filter
-            (n: f n && g (builtins.getAttr n s))
-            (builtins.attrNames s)
-          )
-        )
-      );
-in filterSet
-     (n: !(n=="lib"||n=="overlays"||n=="modules")) # filter out non-packages
-     (p: true) # all packages are ok
-     (import ./default.nix { pkgs = super; })
-

pkgs/default.nix

@@ -0,0 +1,12 @@
+{ pkgs ? import <nixpkgs> {} }:
+{
+  nodeinfo = pkgs.callPackage ./nodeinfo { };
+  lightning-charge = pkgs.callPackage ./lightning-charge { };
+  nanopos = pkgs.callPackage ./nanopos { };
+  spark-wallet = pkgs.callPackage ./spark-wallet { };
+  electrs = (pkgs.callPackage ./electrs { }).rootCrate.build;
+  elementsd = pkgs.callPackage ./elementsd { withGui = false; };
+  hwi = pkgs.callPackage ./hwi { };
+  pylightning = pkgs.python3Packages.callPackage ./pylightning { };
+  liquid-swap = pkgs.python3Packages.callPackage ./liquid-swap { };
+}