From 87358db85e0f7f912ef29f4d334f7ebe500a1425 Mon Sep 17 00:00:00 2001
From: Henrik Lissner <henrik@lissner.net>
Date: Wed, 7 Aug 2019 16:54:47 -0400
Subject: [PATCH] Fix void-function mapcan on Emacs 25.x

---
 core/core-lib.el | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/core/core-lib.el b/core/core-lib.el
index c759a90db..9f3e6df41 100644
--- a/core/core-lib.el
+++ b/core/core-lib.el
@@ -14,6 +14,10 @@
     (defalias 'if-let* #'if-let)
     (defalias 'when-let* #'when-let)
 
+    ;; `mapcan' was introduced in 26.1. `cl-mapcan' isn't a perfect replacement,
+    ;; but it's close enough.
+    (defalias 'mapcan #'cl-mapcan)
+
     (defun alist-get (key alist &optional default remove testfn)
       "Return the value associated with KEY in ALIST.
 If KEY is not found in ALIST, return DEFAULT.