From b5292709cfe28e8be7e181e136fba5c22cfa619f Mon Sep 17 00:00:00 2001
From: "Bernhard M. Wiedemann" <bwiedemann@suse.de>
Date: Sat, 14 Jul 2018 04:52:39 +0200
Subject: [PATCH] Allow to override build date

in order to make builds reproducible.
See https://reproducible-builds.org/ for why this is good
and https://reproducible-builds.org/specs/source-date-epoch/
for the definition of this variable.

This date call works with GNU and BSD variants of date.
---
 Makefile | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 9d7378742..ae0eae74e 100644
--- a/Makefile
+++ b/Makefile
@@ -10,7 +10,11 @@
 # The version number, for release:
 
 VER_VERSION:=0.9.23
-VER_DATE:=$(shell date +"%Y-%m-%d")
+ifdef SOURCE_DATE_EPOCH
+       VER_DATE=$(shell date -u -d "@$(SOURCE_DATE_EPOCH)" "+%Y-%m-%d" 2>/dev/null || date -u -r "$(SOURCE_DATE_EPOCH)" "+%Y-%m-%d" 2>/dev/null || date -u "+%Y-%m-%d")
+else
+       VER_DATE=$(shell date "+%Y-%m-%d")
+endif
 MAGIC_API_VERSION:=0x00000003
 
 # Need to know the OS