[libvirt] Cannot download gnulib

Hi all, When i wanna install libvirt, i happened to following errors. $./autogen.sh I am going to run ./configure with no arguments - if you wish to pass any to it, please specify them on the ./autogen.sh command line. running bootstrap... ./bootstrap: Bootstrapping from checked-out http://libvirt.org sources... ./bootstrap: consider installing git-merge-changelog from gnulib ./bootstrap: getting gnulib files... Submodule 'gnulib' () registered for path '.gnulib' fatal: Needed a single revision Unable to find current revision in submodule path '.gnulib' Failed to bootstrap, please investigate. Could anyone give me some suggestions? Thanks in advance ;-) -- Thanks Harry Wei