From fde27e62b241fb7d96de36a2fd6d7879c24f5de6 Mon Sep 17 00:00:00 2001
From: Jeremy Sowden <jeremy@azazel.net>
Date: Wed, 28 Jan 2026 18:31:07 +0000
Subject: [PATCH] build: support `SOURCE_DATE_EPOCH` for build time-stamp

In order to support reproducible builds, set the build time-stamp to the value
of the environment variable, `SOURCE_DATE_EPOCH`, if set, and fall back to
calling `date`, otherwise.

Link: https://reproducible-builds.org/docs/source-date-epoch/
Fixes: 64c07e38f049 ("table: Embed creating nft version into userdata")
Reported-by: Arnout Engelen <arnout@bzzt.net>
Closes: https://github.com/NixOS/nixpkgs/issues/478048
Suggested-by: Philipp Bartsch <phil@grmr.de>
Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Phil Sutter <phil@nwl.cc>

Upstream-Status: Backport [https://git.netfilter.org/nftables/commit/?id=ca86f206c92704170a295b8dc7a41f6448835dde]
[Adjust patch for 1.1.6]

Signed-off-by: Yi Zhao <yi.zhao@windriver.com>
---
 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 6825474..527049f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -165,7 +165,7 @@ AC_CONFIG_COMMANDS([nftversion.h], [
 ])
 # Current date should be fetched exactly once per build,
 # so have 'make' call date and pass the value to every 'gcc' call
-AC_SUBST([MAKE_STAMP], ["\$(shell date +%s)"])
+AC_SUBST([MAKE_STAMP], ["${SOURCE_DATE_EPOCH:-$(date +%s)}"])
 
 AC_ARG_ENABLE([distcheck],
 	      AS_HELP_STRING([--enable-distcheck], [Build for distcheck]),
-- 
2.34.1

