From 489ca515bea4e0462377d8852b7f29714afcba13 Mon Sep 17 00:00:00 2001
From: Gracjan Polak <gracjan@scrive.com>
Date: Sat, 2 May 2015 11:20:16 +0200
Subject: [PATCH] Make Makefile warn if Emacs is too old.

---
 Makefile | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index 7e4acd289..359aba7ec 100644
--- a/Makefile
+++ b/Makefile
@@ -85,9 +85,20 @@ ELCHECKS=$(addprefix check-, $(ELFILES:.el=))
 	@$(BATCH) \
 		 -f batch-byte-compile $*.el
 
-.PHONY: all compile info clean check $(ELCHECKS) elpa package
-
-all: compile $(AUTOLOADS) info
+.PHONY: all compile info clean check $(ELCHECKS) elpa package check-emacs-version
+
+all: check-emacs-version compile $(AUTOLOADS) info
+
+check-emacs-version :
+	@$(BATCH) --eval "(when (< emacs-major-version 24)					\
+                            (message \"Error: haskell-mode requires Emacs 23 or later\")	\
+                            (message \"Your version of Emacs is %s\" emacs-version)		\
+                            (message \"Found as '$(EMACS)'\")					\
+                            (message \"Use one of:\")						\
+                            (message \"   1.  export EMACS=/path/to/emacs && make\")		\
+                            (message \"   2.  EMACS=/path/to/emacs make\")			\
+                            (message \"   3.  make EMACS=/path/to/emacs\")			\
+                            (kill-emacs 2))"
 
 compile: $(ELCFILES)