don't cross filesystems. usefull if you bind a local mirror into your working copy

makechrootpkg

@@ -109,7 +109,7 @@ umask 000
 if [ ! -d "$copydir" -o "$clean_first" -eq "1" ]; then
     echo "creating clean working copy"
     mkdir -p "$copydir"
-    rsync -a --delete -q -W "$chrootdir/root/" "$copydir"
+    rsync -a --delete -q -W -x "$chrootdir/root/" "$copydir"
 fi
 
 if [ -n "$install_pkg" ]; then