(defcustom dired-omit-case-fold 'filesystem
"Determine whether \"omitting\" patterns are case-sensitive.
When nil, always be case-sensitive; when t, always be
-case-insensitive; the default value, 'filesystem, causes case
+case-insensitive; the default value, `filesystem', causes case
folding to be used on case-insensitive filesystems only."
:type '(choice (const :tag "Always case-sensitive" nil)
(const :tag "Always case-insensitive" t)