From 644bdd220e111d25e43cc5a9f457202b010e9fe9 Mon Sep 17 00:00:00 2001
From: "Bernhard M. Wiedemann" <bwiedemann@suse.de>
Date: Thu, 28 Nov 2019 20:01:50 +0100
Subject: [PATCH] Allow to override build date with SOURCE_DATE_EPOCH

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.

Note: This date call is designed to work with different flavors
of date (GNU, BSD and others).
---
 Makefile | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 9952ee6e..e47e1eff 100644
--- a/Makefile
+++ b/Makefile
@@ -41,6 +41,13 @@ AFL_FUZZ_FILES = $(wildcard src/afl-fuzz*.c)
 
 PYTHON_INCLUDE	?= /usr/include/python2.7
 
+
+ifdef SOURCE_DATE_EPOCH
+    BUILD_DATE ?= $(shell date -u -d "@$(SOURCE_DATE_EPOCH)" -I 2>/dev/null || date -u -r "$(SOURCE_DATE_EPOCH)" -I 2>/dev/null || date -u -I)
+else
+    BUILD_DATE ?= $(shell date -I)
+endif
+
 ifneq "$(filter Linux GNU%,$(shell uname))" ""
   LDFLAGS  += -ldl
 endif
@@ -299,7 +306,7 @@ source-only: all radamsa
 	$(MAKE) -C libtokencap
 
 %.8:	%
-	@echo .TH $* 8 `date -I` "afl++" > $@
+	@echo .TH $* 8 $(BUILD_DATE) "afl++" > $@
 	@echo .SH NAME >> $@
 	@echo .B $* >> $@
 	@echo >> $@