Makefile: avoid flattening `nerdctl-X.Y.Z-go-mod-vendor.tar.gz

Fix issue 1005

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

Makefile

@@ -61,42 +61,43 @@ install:
 	install -D -m 755 $(CURDIR)/extras/rootless/containerd-rootless.sh $(DESTDIR)$(BINDIR)/containerd-rootless.sh
 	install -D -m 755 $(CURDIR)/extras/rootless/containerd-rootless-setuptool.sh $(DESTDIR)$(BINDIR)/containerd-rootless-setuptool.sh
 
-TAR_FLAGS=--transform 's/.*\///g' --owner=0 --group=0
-
 define make_artifact_full_linux
 	DOCKER_BUILDKIT=1 docker build --output type=tar,dest=$(CURDIR)/_output/nerdctl-full-$(VERSION_TRIMMED)-linux-$(1).tar --target out-full --platform $(1) $(CURDIR)
 	gzip -9 $(CURDIR)/_output/nerdctl-full-$(VERSION_TRIMMED)-linux-$(1).tar
 endef
 
+TAR_OWNER0_FLAGS=--owner=0 --group=0
+TAR_FLATTEN_FLAGS=--transform 's/.*\///g'
+
 artifacts: clean
 	GOOS=linux GOARCH=amd64       make -C $(CURDIR)  binaries
-	tar $(TAR_FLAGS) -czvf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-linux-amd64.tar.gz   _output/nerdctl extras/rootless/*
+	tar $(TAR_OWNER0_FLAGS) $(TAR_FLATTEN_FLAGS) -czvf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-linux-amd64.tar.gz   _output/nerdctl extras/rootless/*
 
 	GOOS=linux GOARCH=arm64       make -C $(CURDIR) binaries
-	tar $(TAR_FLAGS) -czvf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-linux-arm64.tar.gz   _output/nerdctl extras/rootless/*
+	tar $(TAR_OWNER0_FLAGS) $(TAR_FLATTEN_FLAGS) -czvf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-linux-arm64.tar.gz   _output/nerdctl extras/rootless/*
 
 	GOOS=linux GOARCH=arm GOARM=7 make -C $(CURDIR) binaries
-	tar $(TAR_FLAGS) -czvf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-linux-arm-v7.tar.gz  _output/nerdctl extras/rootless/*
+	tar $(TAR_OWNER0_FLAGS) $(TAR_FLATTEN_FLAGS) -czvf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-linux-arm-v7.tar.gz  _output/nerdctl extras/rootless/*
 
 	GOOS=linux GOARCH=ppc64le     make -C $(CURDIR) binaries
-	tar $(TAR_FLAGS) -czvf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-linux-ppc64le.tar.gz _output/nerdctl extras/rootless/*
+	tar $(TAR_OWNER0_FLAGS) $(TAR_FLATTEN_FLAGS) -czvf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-linux-ppc64le.tar.gz _output/nerdctl extras/rootless/*
 
 	GOOS=linux GOARCH=s390x       make -C $(CURDIR) binaries
-	tar $(TAR_FLAGS) -czvf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-linux-s390x.tar.gz   _output/nerdctl extras/rootless/*
+	tar $(TAR_OWNER0_FLAGS) $(TAR_FLATTEN_FLAGS) -czvf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-linux-s390x.tar.gz   _output/nerdctl extras/rootless/*
 
 	GOOS=windows GOARCH=amd64     make -C $(CURDIR) binaries
-	tar $(TAR_FLAGS) -czvf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-windows-amd64.tar.gz _output/nerdctl.exe
+	tar $(TAR_OWNER0_FLAGS) $(TAR_FLATTEN_FLAGS) -czvf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-windows-amd64.tar.gz _output/nerdctl.exe
 
 	GOOS=freebsd GOARCH=amd64     make -C $(CURDIR)  binaries
-	tar $(TAR_FLAGS) -czvf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-freebsd-amd64.tar.gz _output/nerdctl
+	tar $(TAR_OWNER0_FLAGS) $(TAR_FLATTEN_FLAGS) -czvf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-freebsd-amd64.tar.gz _output/nerdctl
 
 	rm -f $(CURDIR)/_output/nerdctl $(CURDIR)/_output/nerdctl.exe
 
 	$(call make_artifact_full_linux,amd64)
 	$(call make_artifact_full_linux,arm64)
 
 	go mod vendor
-	tar $(TAR_FLAGS) -czf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-go-mod-vendor.tar.gz go.mod go.sum vendor
+	tar $(TAR_OWNER0_FLAGS) -czf $(CURDIR)/_output/nerdctl-$(VERSION_TRIMMED)-go-mod-vendor.tar.gz go.mod go.sum vendor
 
 .PHONY: \
 	help \