[PATCH 2/2] release: use xz compression

[David Bremner]

This produces tarballs that are roughly 30% smaller.
---
 Makefile.global | 4 ++--
 Makefile.local  | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Makefile.global b/Makefile.global
index 27c82433..e4dbce48 100644
--- a/Makefile.global
+++ b/Makefile.global
@@ -40,9 +40,9 @@ DEB_TAG=debian/$(UPSTREAM_TAG)-1
 RELEASE_HOST=notmuchmail.org
 RELEASE_DIR=/srv/notmuchmail.org/www/releases
 RELEASE_URL=https://notmuchmail.org/releases
-TAR_FILE=$(PACKAGE)-$(VERSION).tar.gz
+TAR_FILE=$(PACKAGE)-$(VERSION).tar.xz
 ELPA_FILE:=$(PACKAGE)-emacs-$(ELPA_VERSION).tar
-DEB_TAR_FILE=$(PACKAGE)_$(VERSION).orig.tar.gz
+DEB_TAR_FILE=$(PACKAGE)_$(VERSION).orig.tar.xz
 SHA256_FILE=$(TAR_FILE).sha256.asc
 GPG_FILE=$(TAR_FILE).asc
 
diff --git a/Makefile.local b/Makefile.local
index 79595925..d16245cb 100644
--- a/Makefile.local
+++ b/Makefile.local
@@ -36,7 +36,7 @@ $(TAR_FILE):
 		--transform s_^_$(PACKAGE)-$(VERSION)/_  \
 		--transform 's_.tmp$$__' --mtime=@$$ct version.tmp
 	rm version.tmp
-	gzip -n < $(TAR_FILE).tmp > $(TAR_FILE)
+	xz -C sha256 -9 < $(TAR_FILE).tmp > $(TAR_FILE)
 	@echo "Source is ready for release in $(TAR_FILE)"
 
 $(SHA256_FILE): $(TAR_FILE)
-- 
2.20.1