all: embrace unit packages where possible

pkgs/unit/zs/zsh-z/package.nix

@@ -0,0 +1,35 @@
+{ stdenv
+, lib
+, fetchFromGitHub
+, installShellFiles
+
+, zsh
+}:
+
+stdenv.mkDerivation {
+  pname = "zsh-z";
+  version = "20210117.g289a4a7";
+
+  src = fetchFromGitHub {
+    owner = "agkozak";
+    repo = "zsh-z";
+    rev = "289a4a7208db9b1778cba71c58fed46dbcea3bc7";
+    sha256 = "016prpavxdzjg372y2700rczdgzjb53bqz5mxjgmvrvjxwj69cf0";
+  };
+
+  nativeBuildInputs = [ installShellFiles ];
+
+  propogatedBuildInputs = [ zsh ];
+
+  installPhase = ''
+    install -D zsh-z.plugin.zsh $out/share/zsh-z/zsh-z.zsh
+    installShellCompletion --zsh _zshz
+  '';
+
+  meta = with lib; {
+    description = ''Jump quickly to directories that you have visited "frecently." A native ZSH port of z.sh.'';
+    homepage = "https://github.com/agkozak/zsh-z";
+    license = licenses.mit;
+    platforms = zsh.meta.platforms;
+  };
+}