Handle ;;;###theme-autoload comments in etc/themes

* lisp/emacs-lisp/loaddefs-gen.el (loaddefs-generate--emacs-batch):
Extract the autoloads and have them loaded along with loaddefs.el.
* etc/NEWS: Mention the new feature.  (Bug#57639)

2 files changed, 13 insertions, 1 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 62004c10a6c..041fe0bdbd8 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -2846,6 +2846,11 @@ Previously, ';;;###' specs inside a top-level form (i.e., something
 like '(when ... ;;;### ...)' would be ignored.  They are now parsed as
 normal.
 
+---
+** Themes have special autoload cookies.
+All build-in themes are scraped for ;;;###theme-autoload cookies that
+are loaded along with the regular auto-loaded code.
+
 +++
 ** 'buffer-modified-p' has been extended.
 This function was previously documented to return only nil or t.  This
diff --git a/lisp/emacs-lisp/loaddefs-gen.el b/lisp/emacs-lisp/loaddefs-gen.el
index d2654fb2064..a1c4f91579e 100644
--- a/lisp/emacs-lisp/loaddefs-gen.el
+++ b/lisp/emacs-lisp/loaddefs-gen.el
@@ -736,7 +736,14 @@ rules for built-in packages and excluded files."
      ;; updated.
      (file-newer-than-file-p
       (expand-file-name "emacs-lisp/loaddefs-gen.el" lisp-directory)
-      output-file))))
+      output-file)))
+  (let ((lisp-mode-autoload-regexp
+           "^;;;###\\(\\(noexist\\)-\\)?\\(theme-autoload\\)"))
+      (loaddefs-generate
+       (expand-file-name "../etc/themes/" lisp-directory)
+       (expand-file-name "theme-loaddefs.el" lisp-directory))))
+
+;;;###autoload (load "theme-loaddefs.el")
 
 (provide 'loaddefs-gen)