Add custom lib

flake.nix

@@ -157,6 +157,7 @@
               specialArgs = {
                 flakeSelf = self;
               };
+              lib = import ./lib {nixpkgs = pkgs;};
               modules =
                 [
                   agenix.nixosModules.default

lib/default.nix

@@ -0,0 +1,8 @@
+{nixpkgs}:
+nixpkgs.lib.extend (final: prev: {
+  toast = let
+    importLib = file: import file {lib = final;};
+  in {
+    patches = importLib ./patches.nix;
+  };
+})

lib/patches.nix

@@ -0,0 +1,13 @@
+{lib}: {
+  /**
+  Get a list of patches from a path.
+  */
+  patchesInPath = path: let
+    pathContents = builtins.readDir path;
+    filter = name: value:
+      (value == "regular" || value == "symlink") && lib.strings.hasSuffix ".patch" name;
+    filteredContents = lib.attrsets.filterAttrs filter pathContents;
+    patchFilenames = builtins.attrNames filteredContents;
+  in
+    builtins.map (value: lib.path.append path value) patchFilenames;
+}