create_tarball: Add option to select compression method

(cherry picked from commit 6a19cd9bb6)

create_tarball

@@ -12,6 +12,13 @@ SUFFIX=${SUFFIX:-"true"}
 # The default is the parent directory (..).
 TARBALL_DIR=${TARBALL_DIR:-".."}
 
+# Set compression method
+case ${COMPRESS:="xz"} in
+  "gzip") TAR_SUFFIX="gz";;
+  "bzip2") TAR_SUFFIX="bz2";;
+  "xz") TAR_SUFFIX="xz";;
+esac
+
 # Check git-dir
 if [[ ! -e .git ]] ||
    [[ -z "`git rev-parse --git-dir 2>/dev/null`" ]]; then
@@ -80,12 +87,12 @@ fi
 
 # Create tarball
 echo "Package name: $package"
-if [ ! -e $TARBALL_DIR/$package.tar.xz ]; then
+if [ ! -e $TARBALL_DIR/$package.tar.$TAR_SUFFIX ]; then
   echo "Creating tarball in $TARBALL_DIR."
   trap "rm $TARBALL_DIR/tar-$$; exit 1" INT
   tar c --owner=root --group=users --exclude .git --exclude .gitmodules --transform "s|^\.|$package|" ./ | \
-  xz -9 >$TARBALL_DIR/tar-$$ && \
-  mv $TARBALL_DIR/tar-$$ $TARBALL_DIR/$package.tar.xz || \
+  $COMPRESS -9 >$TARBALL_DIR/tar-$$ && \
+  mv $TARBALL_DIR/tar-$$ $TARBALL_DIR/$package.tar.$TAR_SUFFIX || \
   rm $TARBALL_DIR/tar-$$
 else
   echo "Unchanged tarball in $TARBALL_DIR."