build: Switch default dpkg-deb compression from gzip to xz

Keep building dpkg.deb with gzip to make debootstrap life easier
on non-Debian based systems.

configure.ac

@@ -32,7 +32,7 @@ DPKG_WITH_DIR([logdir], [${localstatedir}/log],
               [system logging directory [LOCALSTATEDIR/log]])
 
 # Set default dpkg-deb compressor
-DPKG_DEB_COMPRESSOR([gzip])
+DPKG_DEB_COMPRESSOR([xz])
 
 # Checks for programs.
 AC_PROG_CC

debian/changelog

@@ -123,6 +123,8 @@ dpkg (1.17.0) UNRELEASED; urgency=low
   * Document --file and --label parser options in dpkg-parsechangelog(1).
   * Add a new configure --with-dpkg-deb-compressor option to allow selecting
     the default dpkg-deb compressor, mainly for downstreams.
+  * Switch dpkg-deb default compressor from gzip to xz. Build dpkg.deb using
+    gzip to make debootstrap life easier on non-Debian based systems.
 
   [ Updated programs translations ]
   * Fix typo in Spanish translation of update-alternatives.

debian/rules

@@ -116,7 +116,10 @@ binary-arch: install
 	dh_shlibdeps -a
 	dh_gencontrol -a
 	dh_md5sums -a
-	dh_builddeb -a
+	# Make debootstrap life easier on non-Debian based systems by
+	# compressing dpkg.deb with gzip instead of xz.
+	dh_builddeb -pdpkg -- -Zgzip
+	dh_builddeb -a -Ndpkg
 
 # Put together the dpkg-dev package
 binary-indep: install