From 7ec3975c9a553f4eee9b05aef8296a8c44e47cef Mon Sep 17 00:00:00 2001
From: "Basil L. Contovounesios" <contovob@tcd.ie>
Date: Sun, 31 Jan 2021 12:44:53 +0000
Subject: [PATCH] Avoid deleting docs in old Emacs versions

* Makefile (maintainer-clean): Check minimum supported Emacs version
before deleting docs, to ensure they can be regenerated.
---
 Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Makefile b/Makefile
index b587c49..efee2db 100644
--- a/Makefile
+++ b/Makefile
@@ -54,7 +54,10 @@ clean:
 	$(RM) $(ELCS)
 .PHONY: clean
 
+maintainer-clean: VER := 26
+maintainer-clean: MSG := Doc regeneration requires $(VER)+
 maintainer-clean: clean
+	$(BATCH) -eval '(if (< emacs-major-version $(VER)) (error "$(MSG)"))'
 	$(RM) $(DOCS)
 .PHONY: maintainer-clean