From 70f31c66e4e8b0d3a2b9a66a3edfed74f991c2a4 Mon Sep 17 00:00:00 2001
From: Vagrant Cascadian <vagrant@reproducible-builds.org>
Date: Wed, 14 Jul 2021 14:27:53 +0000
Subject: [PATCH 3/3] Makefile.in: Set timestamp from SOURCE_DATE_PEOCH
 environment variable.

https://reproducible-builds.org/docs/source-date-epoch/
---
 Makefile.in | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Makefile.in b/Makefile.in
index 8fa86d69..e44ca4b8 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -46,7 +46,14 @@ maintainer-clean: distclean
 # Rule to make a tarball exclusive all kinds of fluff
 #
 
-TIMESTAMP       = $(shell date +%Y%m%d)
+# Set TIMESTAMP from SOURCE_DATE_EPOCH
+# https://reproducible-builds.org/docs/source-date-epoch/
+DATE_FMT = +%Y%m%d
+ifdef SOURCE_DATE_EPOCH
+    TIMESTAMP ?= $(shell date -u -d "@$(SOURCE_DATE_EPOCH)" "$(DATE_FMT)" 2>/dev/null || date -u -r "$(SOURCE_DATE_EPOCH)" "$(DATE_FMT)" 2>/dev/null || date -u "$(DATE_FMT)")
+else
+    TIMESTAMP ?= $(shell date "$(DATE_FMT)")
+endif
 TAR_DIR         = $(versioneddir)
 TAR_FILE	      = $(versioneddir).tar
 
-- 
2.32.0