File reproducible.patch of Package tiptop

From: Bernhard M. Wiedemann <bwiedemann suse de>
Date: 2020-11-08
Subject: make package build reproducible
References: boo#1047218, boo#1084909
Upstream: submitted

https://bugzilla.opensuse.org/show_bug.cgi?id=1047218
https://bugzilla.opensuse.org/show_bug.cgi?id=1084909

Allow to override hostname and build date

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 works with different `date` implementations.

Also consistently use ISO 8601 date format to be understood everywhere.
Also use UTC to be independent of timezone.
Index: tiptop-2.3.1/src/Makefile.in
===================================================================
--- tiptop-2.3.1.orig/src/Makefile.in
+++ tiptop-2.3.1/src/Makefile.in
@@ -46,10 +46,17 @@ Makefile: Makefile.in ../config.status
 	cd .. && ./config.status --recheck
 
 
+DATE_FMT = -Iseconds
+ifdef SOURCE_DATE_EPOCH
+    BUILD_DATE ?= $(shell date -u -d "@$(SOURCE_DATE_EPOCH)" "$(DATE_FMT)" 2>/dev/null || date -u -r "$(SOURCE_DATE_EPOCH)" "$(DATE_FMT)" 2>/dev/null || date -u "$(DATE_FMT)")
+else
+    BUILD_DATE ?= $(shell date "$(DATE_FMT)")
+endif
+
 
 version.o: version.c
-	$(CC) $(CFLAGS) -DCOMPILE_HOST="\""`hostname`"\"" \
-                        -DCOMPILE_DATE="\"`date`\"" \
+	$(CC) $(CFLAGS) -DCOMPILE_HOST="\""$${HOSTNAME:-`hostname`}"\"" \
+                        -DCOMPILE_DATE="\"$(BUILD_DATE)\"" \
                         -c $(srcdir)/version.c