feat(sterni/emacs): enable server and include emacsclient

Change-Id: Icaf22595c774bdceb7e79f5302cde8d039aa3b09
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5401
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Autosubmit: sterni <sternenseemann@systemli.org>

users/sterni/emacs/default.nix

@@ -65,10 +65,16 @@ let
 in
 
 # sadly we can't give an init-file via the command line
-pkgs.writeShellScriptBin "emacs" ''
+(pkgs.writeShellScriptBin "emacs" ''
   exec ${emacs}/bin/emacs          \
     --no-init-file                 \
     --directory ${configDirectory} \
     --eval "(require 'init)"       \
     "$@"
-''
+'').overrideAttrs (super: {
+  buildCommand = ''
+    ${super.buildCommand}
+
+    ln -s "${emacs}/bin/emacsclient" "$out/bin/emacsclient"
+  '';
+})

users/sterni/emacs/init.el

@@ -248,6 +248,9 @@
   (evil-define-key 'normal 'global (kbd "<leader>ls") 'languagetool-set-language)
   (evil-define-key 'normal 'global (kbd "<leader>lr") 'languagetool-clear-buffer))
 
+(unless (server-running-p)
+  (server-start))
+
 (require 'subscriptions)
 (require 'nix-inject)