Emacs: Only use :extend in faces in Emacs >= 27.

init.d/basics/ui.el

@@ -1,6 +1,6 @@
 ;;; ui.el --- Configure user interfaces. -*- lexical-binding: t; -*-
 
-;; Time-stamp: <2020-04-21T04:20:50+0200>
+;; Time-stamp: <2020-04-22T03:16:48+0200>
 
 ;;; Commentary:
 ;; * treemacs
@@ -20,8 +20,10 @@
   :config (progn
             (make-face 'hl-line-treemacs-face)
             (set-face-attribute 'hl-line-treemacs-face nil
-                                :background "#080011"
-                                :extend t)
+                                :background "#080011")
+            (when (>= emacs-major-version 27)
+              (set-face-attribute 'hl-line-treemacs-face nil
+                                  :extend t))
             (defun my/treemacs-set-hl-line ()
               (set (make-local-variable 'hl-line-face)
                    'hl-line-treemacs-face)))