reproducible debian: build: support old stretch's diffoscope that doesn't take --timeout

Signed-off-by: Mattia Rizzolo <mattia@debian.org>

bin/reproducible_build.sh

@@ -333,7 +333,7 @@ diffoscope_timed_out() {
 }
 
 call_diffoscope_on_changes_files() {
-	local TMPLOG TIMEOUT TEMP MSG_PART1 session diffoscope_version
+	local TMPLOG TIMEOUT DIFFOSCOPE_TIMEOUT TEMP MSG_PART1 session diffoscope_version
 	# DIFFOSCOPE is globally used
 	# filter lines describing .buildinfo files from .changes file
 	sed -i -e '/^ [a-f0-9]\{32,64\} .*\.buildinfo$/d' b{1,2}/$CHANGES
@@ -368,15 +368,18 @@ call_diffoscope_on_changes_files() {
 
 	# we have a working diffoscope!
 	log_info "$DIFFOSCOPE will be used to compare the two builds:"
+	if [ $(echo $DIFFOSCOPE_VERSION | awk '{print $2}') -ge 202 ]; then
+		# this --timeout 120m below is arbitrary and can be subject to further evaluation later
+		DIFFOSCOPE_TIMEOUT="--timeout $(( 120 * 60 ))"
+	fi
 	set -x
 	set +e
-	# the --timeout 120m below is arbitrary and can be subject to further evaluation later
 	( timeout 155m nice schroot \
 		--directory $TMPDIR \
 		--run-session \
 		-c "$session" \
 		-- sh -c "export TMPDIR=$TEMP ; timeout $TIMEOUT diffoscope \
-			--timeout $(( 120 * 60 )) \
+			${DIFFOSCOPE_TIMEOUT-} \
 			--html $TMPDIR/${DBDREPORT} \
 			--text $TMPDIR/$DBDTXT \
 			--json $TMPDIR/$DBDJSON \