; * lisp/so-long.el: Backwards-compatibility fix for Emacs < 27

We support Emacs 24.4 and later (for ELPA releases), and ad-find-advice
only changed from a macro to a function in Emacs 27, so this change is
to restore compatibility with older versions where we do need the macro
definition loaded at byte-compilation time.

This effectively combines the related changes from:

- commit 986c12b20f
- commit c221db0402

lisp/so-long.el

@@ -2028,7 +2028,10 @@ If it appears in `%s', you should remove it."
   ;; Update to version 1.0 from earlier versions:
   (when (version< so-long-version "1.0")
     (remove-hook 'change-major-mode-hook 'so-long-change-major-mode)
-    (require 'advice) ;; It should already be loaded, but just in case.
+    (require 'advice)
+    ;; `ad-find-advice' is a macro in Emacs 26 and earlier.
+    (eval-when-compile (when (< emacs-major-version 27)
+                         (require 'advice)))
     (declare-function ad-find-advice "advice")
     (declare-function ad-remove-advice "advice")
     (declare-function ad-activate "advice")