Update gccemacs support

To add support for "update 11", see:
http://akrl.sdf.org/gccemacs.html#org4b11ea1

Also:
+ Move eln files to ~/.emacs.d/.local/cache/eln
+ Disable comp-deferred-compilation by default (now that it is
  enabled-by-default upstream).

core/cli/packages.el

@@ -126,8 +126,14 @@ list remains lean."
       (doom-log "%s is newer than %s" file elc-file)
       t)))
 
+;; DEPRECATED Remove later
+(defun doom--comp-output-filename (file)
+  (if (fboundp 'comp-output-filename)
+      (comp-output-filename file)
+    (comp-el-to-eln-filename file)))
+
 (defun doom--eln-file-outdated-p (file)
-  (when-let* ((eln-file (comp-output-filename file))
+  (when-let* ((eln-file (doom--comp-output-filename file))
               (error-file (concat eln-file ".error")))
     (push eln-file doom--expected-eln-files)
     (cond ((file-exists-p eln-file)
@@ -144,7 +150,7 @@ list remains lean."
 
 (defun doom--native-compile-done-h (file)
   (when-let* ((file)
-              (eln-file (comp-output-filename file))
+              (eln-file (doom--comp-output-filename file))
               (error-file (concat eln-file ".error")))
     (if (file-exists-p eln-file)
         (doom-log "Compiled %s" eln-file)

core/core-packages.el

@@ -97,9 +97,7 @@ uses a straight or package.el command directly).")
       ;; we don't have to deal with them at all.
       autoload-compute-prefixes nil
       ;; We handle it ourselves
-      straight-fix-org nil
-      ;; HACK Disable native-compilation for some troublesome files
-      comp-deferred-compilation-black-list '("/evil-collection-vterm\\.el$"))
+      straight-fix-org nil)
 
 (with-eval-after-load 'straight
   ;; `let-alist' is built into Emacs 26 and onwards

core/core.el

@@ -269,6 +269,17 @@ config.el instead."
   (let ((user-init-file custom-file))
     (apply orig-fn args)))
 
+;; For gccemacs users: http://akrl.sdf.org/gccemacs.html
+(after! comp
+  ;; Prevent unwanted runtime builds; packages are compiled ahead-of-time when
+  ;; they are installed and site files are compiled when gccemacs is installed.
+  (setq comp-deferred-compilation nil)
+  ;; Don't store eln files in ~/.emacs.d; it's likely to be purged when
+  ;; upgrading Doom.
+  (add-to-list 'comp-eln-load-path (concat doom-cache-dir "eln/"))
+  ;; HACK Disable native-compilation for some troublesome packages
+  (add-to-list 'comp-deferred-compilation-black-list "/evil-collection-vterm\\.el\\'"))
+
 
 ;;
 ;;; Optimizations