feat(wpcarro/emacs): Package vector.el

Paying-off more packaging debt...

Change-Id: Ide641229d6c8efe70c0fd6c625d07aa1a3be98a0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7395
Tested-by: BuildkiteCI
Reviewed-by: wpcarro <wpcarro@gmail.com>

users/wpcarro/emacs/pkgs/vector/default.nix

@@ -0,0 +1,21 @@
+{ pkgs, depot, ... }:
+
+let
+  vector = pkgs.callPackage
+    ({ emacsPackages }:
+      emacsPackages.trivialBuild {
+        pname = "vector";
+        version = "1.0.0";
+        src = ./vector.el;
+      })
+    { };
+
+  emacs = (pkgs.emacsPackagesFor pkgs.emacs28).emacsWithPackages (epkgs: [ vector ]);
+in
+vector.overrideAttrs (_old: {
+  doCheck = true;
+  checkPhase = ''
+    ${emacs}/bin/emacs -batch \
+      -l ert -l ${./tests.el} -f ert-run-tests-batch-and-exit
+  '';
+})