fix(auto-dark-mode): do not error out if dark mode not possible

configuration.org

@@ -1067,7 +1067,12 @@ My favorite theme despite occasional low contrast.
     :custom
     (auto-dark-themes '((modus-vivendi) (modus-operandi)))
     :init
-    (auto-dark-mode))
+    ;; This major mode initialization will signal an error if it cannot find a
+    ;; valid dark/light mode detection method.  Not all computers work with this
+    ;; major mode.  Eat the error and carry on.
+    (condition-case dark-err
+        (auto-dark-mode)
+      (error (message "Could not activate auto-dark-mode.  Carry on."))))
 #+end_src
 ** A facility to streamline theme selection
 #+BEGIN_SRC emacs-lisp