add config-dir variable and change load-path to use it

settings/syntax-checking-settings.el

@@ -18,9 +18,9 @@
 ;; do not load directly with e.g. (global-flycheck-mode) or via
 ;; after-init-hook while loading the init because flycheck will freeze
 ;; for a short while. Therefore better defer loading.
-;;(require 'flycheck (concat user-emacs-directory "lisp/flycheck/flycheck.el"))
+;;(require 'flycheck (concat config-dir "lisp/flycheck/flycheck.el"))
 (use-package flycheck
-  :load-path "lisp/flycheck"
+  :load-path (lambda() (concat config-dir "lisp/flycheck"))
   :defer 2
   :init
   (setq flycheck-mode-line-prefix "𝓕")  ;; Ⓕ 𝓕 ✈ f  ;; other flycheck settings see syntax-checking-settings.el