(BREAKING) Don't host-namespace local files

Local cache and data files were stored in a parent folder named after
your host, because I'd symlink the same config across computers via
dropbox. This would cause byte-compile issues in packages, so I stopped
doing this.

Now that each computer gets its own clone, host-namespaced local
directories are unnecessary. There's no other benefit to having them.

core/core-packages.el

@@ -140,7 +140,7 @@ startup."
     (setq load-path doom--base-load-path
           package-activated-list nil)
     ;; Ensure core folders exist
-    (dolist (dir (list doom-local-dir doom-etc-dir doom-cache-dir package-user-dir))
+    (dolist (dir (list doom-local-dir doom-etc-dir doom-cache-dir doom-packages-dir))
       (unless (file-directory-p dir)
         (make-directory dir t)))
     (condition-case _ (package-initialize t)

core/core.el

@@ -25,7 +25,7 @@
   "If non-nil, all doom functions will be verbose. Set DEBUG=1 in the command
 line or use --debug-init to enable this.")
 
-(defvar doom-emacs-dir (expand-file-name user-emacs-directory)
+(defvar doom-emacs-dir (file-truename user-emacs-directory)
   "The path to this emacs.d directory.")
 
 (defvar doom-core-dir (concat doom-emacs-dir "core/")
@@ -34,38 +34,29 @@ line or use --debug-init to enable this.")
 (defvar doom-modules-dir (concat doom-emacs-dir "modules/")
   "Where configuration modules are stored.")
 
-
-;; Multi-host directories: I namespace `doom-etc-dir' and `doom-cache-dir' with
-;; host names because I use the same (often symlinked) emacs.d across several
-;; computers -- often simultaneously. Cache or other temporary files would
-;; conflict otherwise.
-
 (defvar doom-local-dir (concat doom-emacs-dir ".local/")
   "Root directory for local Emacs files. Use this as permanent storage for files
 that are safe to share across systems (if this config is symlinked across
 several computers).")
 
-(defvar doom-host-dir (concat doom-local-dir "@" (system-name))
+(defvar doom-etc-dir (concat doom-local-dir "etc/")
-  "Directory for hostname-specific file storage. Used by `doom-etc-dir' and
+  "Directory for non-volatile storage. For volatile story, see `doom-cache-dir'.
-`doom-cache-dir'.")
 
-(defvar doom-etc-dir (concat doom-host-dir "/etc/")
+Use this for dependencies like servers or config files that are stable (i.e. it
-  "Host-namespaced directory for non-volatile storage. These are not deleted or
+should be unlikely that you need to delete them if something goes wrong).")
-tampored with by DOOM functions. Use this for dependencies like servers or
-config files that are stable (i.e. it should be unlikely that you need to delete
-them if something goes wrong).")
 
-(defvar doom-cache-dir (concat doom-host-dir "/cache/")
+(defvar doom-cache-dir (concat doom-local-dir "cache/")
-  "Host-namespaced directory for volatile storage. Deleted when `doom/reset' is
+  "Directory for volatile storage.
-called. Use this for transient files that are generated on the fly like caches
+
-and temporary files. Anything that may need to be cleared if there are
+Deleted when `doom/reset' is called. Use this for transient files; on-the-fly
-problems.")
+like caches and temporary files. Anything that you don't mind deleting if there
+are problems.")
 
 (defvar doom-packages-dir (concat doom-local-dir "packages/")
   "Where package.el and quelpa plugins (and their caches) are stored.")
 
 (defvar doom-autoload-file (concat doom-local-dir "autoloads.el")
-  "Location of the autoloads file generated by `doom/reload-autoloads'.")
+  "Where `doom//reload-autoloads' will generate its autoloads file.")
 
 (defgroup doom nil
   "DOOM Emacs, an Emacs configuration for a stubborn, shell-dwelling and