Helper for packaging/grabbing osx apps; use it for OBS, keycastr, vlc

nix/system/worktop/darwin-configuration.nix

@@ -1,5 +1,35 @@
 { config, pkgs, ... }:
+let
+  obs-studio = pkgs.callPackage ./makeApp.nix rec {
+    name = "OBS";
+    version = "29.1.1";
+    src = pkgs.fetchurl {
+      url = "https://cdn-fastly.obsproject.com/downloads/obs-studio-${version}-macos-arm64.dmg";
+      sha256 = "07rhswgx3zqpn32n4ipf34zjjm2cx8fmrb7gliiw6hskwcbbs3yi";
+    };
+  };
 
+  vlc =
+    pkgs.callPackage ./makeApp.nix rec {
+      name = "VLC";
+      version = "3.0.18";
+      sourceRoot = "${name}.app";
+      src = pkgs.fetchurl {
+        url = "https://get.videolan.org/vlc/3.0.18/macosx/vlc-${version}-arm64.dmg";
+        sha256 = "0iwgcrwcfyw0r41kjx4hx1sy37mzx5q8nlbzh58gs8ajpjymkhlr";
+      };
+    };
+
+  keycastr =
+    pkgs.callPackage ./makeApp.nix rec {
+      name = "KeyCastr";
+      version = "0.9.13";
+      src = pkgs.fetchurl {
+        url = "https://github.com/keycastr/keycastr/releases/download/v${version}/KeyCastr.app.zip";
+        sha256 = "1pp0gslq53azhbbyxp12gjy9iaysrf56l16swqdaf4z21p7iag7k";
+      };
+    };
+in
 {
 
   nixpkgs.config.allowUnfree = true;
@@ -15,9 +45,11 @@
       pkgs.slack
       pkgs._1password
       pkgs.tailscale
+      obs-studio
+      vlc
+      keycastr
+
       # wishlist
-      # LICEcap
-      # keycastr
       # todo (unsupported on aarch64-darwin):
       # pkgs.spotify
       # pkgs.firefox