beesh.sh: use pbzip2 for saving build environment when available

src/beesh.sh.in

@@ -667,6 +667,8 @@ function bee_pkg_pack() {
 
 
 function bee_archivebuild() {
+    local TAROPTS='-j'
+
     [ "${OPT_ARCHIVE_BUILD}" != "yes" ] && return
 
     if [ ! -d "${BEE_BUILDARCHIVEDIR}" ] ; then
@@ -682,7 +684,11 @@ function bee_archivebuild() {
         B=${BEEWORKDIR}/build
     fi
 
-    tar -cjf ${archive} \
+    if type -p pbzip2 > /dev/null ; then
+      TAROPTS="-I pbzip2"
+    fi
+
+    tar ${TAROPTS} -cf ${archive} \
         --show-transformed-names \
         --sparse \
         --absolute-names \