Globally define private userdata directory

This is instead of repeating the path again and again in the code.  It's cleaner
this way, also easier to spot mistakes (see the now fixed definition for
`abbrev-file-name' …).

init.el

@@ -26,18 +26,21 @@
                    (file-chase-links load-file-name))
   "The giant turtle on which the world rests.")
 
-(defconst on-windows (memq system-type '(windows-nt cygwin))
-  "Non-nil if and only if this instance of Emacs runs on Windows.")
-
-(setq custom-file (expand-file-name "private/custom.el" emacs-d)
-      custom-theme-directory (expand-file-name "themes/" emacs-d))
-
 (add-to-list 'load-path (expand-file-name "site-lisp" emacs-d))
 
-;; Ensure that ~/.emacs.d/private exists, because we want to store data there
-(let ((private-data-dir (expand-file-name "private/" emacs-d)))
-  (unless (file-directory-p private-data-dir)
-    (make-directory private-data-dir)))
+(defvar emacs-d-userdata (expand-file-name "private/" emacs-d)
+  "Directory to store user data in.")
+
+;; Ensure that `emacs-d-userdata' exists as a directory, because we want to
+;; store data there.
+(unless (file-directory-p emacs-d-userdata)
+  (make-directory emacs-d-userdata))
+
+(setq custom-file (expand-file-name "custom.el" emacs-d-userdata)
+      custom-theme-directory (expand-file-name "themes/" emacs-d))
+
+(defconst on-windows (memq system-type '(windows-nt cygwin))
+  "Non-nil if and only if this instance of Emacs runs on Windows.")
 
 
 ;; * Packages
@@ -504,7 +507,7 @@
 
 (use-package savehist
   :commands (savehist-mode)
-  :init (setq savehist-file (expand-file-name "private/savehist" emacs-d)))
+  :init (setq savehist-file (expand-file-name "savehist" emacs-d-userdata)))
 
 (use-package server
   :commands (server-running-p server-start)
@@ -521,7 +524,7 @@
             (tab-bar-history-mode +1)))
 
 (use-package url
-  :init (setq url-configuration-directory (expand-file-name "private/url" emacs-d)))
+  :init (setq url-configuration-directory (expand-file-name "url" emacs-d-userdata)))
 
 (use-package window
   :init (setq switch-to-buffer-obey-display-actions t
@@ -644,10 +647,10 @@
               projectile-completion-system 'helm
               projectile-ignored-project-function #'file-remote-p
               projectile-create-missing-test-files t
-              projectile-known-projects-file (expand-file-name "private/projectile-bookmarks.eld"
-                                                               emacs-d)
-              projectile-cache-file (expand-file-name "private/projectile.cache"
-                                                      emacs-d))
+              projectile-known-projects-file (expand-file-name "projectile-bookmarks.eld"
+                                                               emacs-d-userdata)
+              projectile-cache-file (expand-file-name "projectile.cache"
+                                                      emacs-d-userdata))
   :diminish projectile-mode)
 
 
@@ -662,7 +665,7 @@
 
 (use-package abbrev
   :init (setq save-abbrevs 'silently
-              abbrev-file-name (expand-file-name "private/abbrev_defs"))
+              abbrev-file-name (expand-file-name "abbrev_defs" emacs-d-userdata))
   :diminish abbrev-mode)
 
 (use-package dictionary
@@ -1081,7 +1084,7 @@
                                                               (list "GOTO"))
                                                       "ATTN"))))
                 org-clock-persist t
-                org-clock-persist-file (expand-file-name "private/org-clock-save.el" emacs-d)
+                org-clock-persist-file (expand-file-name "org-clock-save.el" emacs-d-userdata)
                 org-clock-persist-query-resume nil
                 org-clock-ask-before-exiting nil
                 org-time-stamp-rounding-minutes '(1 1))
@@ -1611,7 +1614,7 @@ point to the beginning of buffer first."
       gnus-home-directory (expand-file-name "~/.config/gnus-news")
       gnus-directory gnus-home-directory
       gnus-kill-files-directory gnus-directory
-      gnus-startup-file (expand-file-name "private/gnus-newsrc" emacs-d)
+      gnus-startup-file (expand-file-name "gnus-newsrc" emacs-d-userdata)
       gnus-cache-directory (expand-file-name "cache/" gnus-directory)
       gnus-verbose 6
       gnus-dbus-close-on-sleep t
@@ -1987,8 +1990,7 @@ point to the beginning of buffer first."
 (use-package nsm
   :init (setq network-security-level 'high
               nsm-save-host-names t
-              nsm-settings-file (expand-file-name
-                                 "~/.emacs.d/private/network-security.data"))
+              nsm-settings-file (expand-file-name "network-security.data" emacs-d-userdata))
   :config (advice-add 'nsm-write-settings
                       :before #'db/sort-nsm-permanent-settings))
 
@@ -2312,7 +2314,7 @@ point to the beginning of buffer first."
              counsel-shell-history))
 
 (use-package smex
-  :init (setq smex-save-file (expand-file-name "private/smex-items" emacs-d)))
+  :init (setq smex-save-file (expand-file-name "smex-items" emacs-d-userdata)))
 
 (use-package swiper
   :ensure t
@@ -2322,7 +2324,7 @@ point to the beginning of buffer first."
 (use-package recentf
   :commands (recentf-mode recentf-save-list)
   :init (setq recentf-max-saved-items 1000
-              recentf-save-file (expand-file-name "private/recentf" emacs-d))
+              recentf-save-file (expand-file-name "recentf" emacs-d-userdata))
   :config (run-with-timer 0 3600 #'recentf-save-list))
 
 (use-package company
@@ -2412,8 +2414,7 @@ eventuelly be set to nil, however)."
               bm-wrap-search t))
 
 (use-package bookmark
-  :init (setq bookmark-default-file (expand-file-name "private/bookmarks"
-                                                      emacs-d)
+  :init (setq bookmark-default-file (expand-file-name "bookmarks" emacs-d-userdata)
               bookmark-menu-confirm-deletion t))
 
 (use-package dumb-jump
@@ -2471,10 +2472,10 @@ eventuelly be set to nil, however)."
               emms-stream-default-action "play"
               emms-track-description-function 'db/emms-track-description
               emms-playlist-default-major-mode 'emms-playlist-mode
-              emms-cache-file (expand-file-name "private/emms/cache" emacs-d)
-              emms-history-file (expand-file-name "private/emms/history" emacs-d)
-              emms-score-file (expand-file-name "private/emms/scores" emacs-d)
-              emms-stream-bookmarks-file (expand-file-name "private/emms/streams" emacs-d))
+              emms-cache-file (expand-file-name "emms/cache" emacs-d-userdata)
+              emms-history-file (expand-file-name "emms/history" emacs-d-userdata)
+              emms-score-file (expand-file-name "emms/scores" emacs-d-userdata)
+              emms-stream-bookmarks-file (expand-file-name "emms/streams" emacs-d-userdata))
   :config (progn
 
             ;; Initialization copied and adapted from `emms-setup’
@@ -2675,8 +2676,8 @@ eventuelly be set to nil, however)."
               eshell-hist-ignoredups t
               eshell-save-history-on-exit t
               eshell-history-size 5000
-              eshell-history-file-name (expand-file-name "private/eshell/history" emacs-d)
-              eshell-last-dir-ring-file-name (expand-file-name "private/eshell/lastdir" emacs-d)
+              eshell-history-file-name (expand-file-name "eshell/history" emacs-d-userdata)
+              eshell-last-dir-ring-file-name (expand-file-name "eshell/lastdir" emacs-d-userdata)
               eshell-destroy-buffer-when-process-dies t
               eshell-prompt-function #'eshell/default-prompt-function
               eshell-prompt-regexp "└─[$#] "
@@ -3062,8 +3063,7 @@ eventuelly be set to nil, however)."
   :commands (er/expand-region))
 
 (use-package eww
-  :init (setq eww-bookmarks-directory
-              (expand-file-name "private/" emacs-d)))
+  :init (setq eww-bookmarks-directory emacs-d-userdata))
 
 (use-package haskell-mode
   :config (progn