gcc_release (XZ): Default to xz --best.

2017-05-23  Matthias Klose  <doko@ubuntu.com>

        * gcc_release (XZ): Default to xz --best.

From-SVN: r248392

maintainer-scripts/ChangeLog

+2017-05-23  Matthias Klose  <doko@ubuntu.com>
+
+	* gcc_release (XZ): Default to xz --best.
+
 2017-05-18  Matthias Klose  <doko@ubuntu.com>
 
 	* gcc_release (build_gzip): Build xz tarball instead of bz2 tarball.

maintainer-scripts/gcc_release

@@ -548,7 +548,7 @@ FILE_LIST=""
 # Programs we use.
 
 BZIP2="${BZIP2:-bzip2}"
-XZ="${XZ:-xz}"
+XZ="${XZ:-xz --best}"
 CVS="${CVS:-cvs -f -Q -z9}"
 DIFF="${DIFF:-diff -Nrcpad}"
 ENV="${ENV:-env}"